Was finally able to reproduce under valgrind with the OFX/QFX import plugin!

==18084== Invalid read of size 8
==18084==    at 0x943FD06: g_type_check_instance_cast (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x538DE78: gnc_tree_view_account_set_selected_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-gnome-utils.so)
==18084==    by 0x1D6707DC: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CD3D: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x67945E5: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x669738A: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CAC7: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==  Address 0x31db4890 is 976 bytes inside a block of size 1,112 free'd
==18084==    at 0x4C30D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x943EA12: g_type_free_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66F62E9: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419E80: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CEB1: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66BC95F: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9420647: g_object_run_dispose (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x65E8C84: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==  Block was alloc'd at
==18084==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x6BF8858: g_malloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10675: g_slice_alloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10B28: g_slice_alloc0 (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x943E715: g_type_create_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x941F5A7: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942141F: g_object_new_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9421798: g_object_new (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x538C02B: gnc_tree_view_account_new_with_root (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-gnome-utils.so)
==18084==    by 0x1D67013F: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6707CE: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==
sys:1: Warning: invalid unclassed pointer in cast to 'GtkTreeView'
==18084== Invalid read of size 8
==18084==    at 0x678F50E: gtk_tree_view_scroll_to_cell (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x538DE8F: gnc_tree_view_account_set_selected_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-gnome-utils.so)
==18084==    by 0x1D6707DC: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CD3D: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x67945E5: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x669738A: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CAC7: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==  Address 0x31db4890 is 976 bytes inside a block of size 1,112 free'd
==18084==    at 0x4C30D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x943EA12: g_type_free_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66F62E9: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419E80: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CEB1: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66BC95F: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9420647: g_object_run_dispose (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x65E8C84: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==  Block was alloc'd at
==18084==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x6BF8858: g_malloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10675: g_slice_alloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10B28: g_slice_alloc0 (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x943E715: g_type_create_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x941F5A7: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942141F: g_object_new_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9421798: g_object_new (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x538C02B: gnc_tree_view_account_new_with_root (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-gnome-utils.so)
==18084==    by 0x1D67013F: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6707CE: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==
==18084== Invalid read of size 8
==18084==    at 0x943F677: g_type_check_instance_is_a (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x678F525: gtk_tree_view_scroll_to_cell (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x538DE8F: gnc_tree_view_account_set_selected_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-gnome-utils.so)
==18084==    by 0x1D6707DC: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CD3D: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x67945E5: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x669738A: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==  Address 0x31db4890 is 976 bytes inside a block of size 1,112 free'd
==18084==    at 0x4C30D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x943EA12: g_type_free_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66F62E9: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419E80: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CEB1: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66BC95F: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9420647: g_object_run_dispose (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x65E8C84: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==  Block was alloc'd at
==18084==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x6BF8858: g_malloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10675: g_slice_alloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10B28: g_slice_alloc0 (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x943E715: g_type_create_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x941F5A7: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942141F: g_object_new_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9421798: g_object_new (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x538C02B: gnc_tree_view_account_new_with_root (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-gnome-utils.so)
==18084==    by 0x1D67013F: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6707CE: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==
sys:1: GtkWarning: IA__gtk_tree_view_scroll_to_cell: assertion 'GTK_IS_TREE_VIEW (tree_view)' failed
==18084== Invalid read of size 8
==18084==    at 0x944017D: g_type_check_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9432DD2: g_signal_connect_data (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x1D670814: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CD3D: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x67945E5: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x669738A: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419F6C: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CAC7: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==  Address 0x31db4890 is 976 bytes inside a block of size 1,112 free'd
==18084==    at 0x4C30D3B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x943EA12: g_type_free_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66F62E9: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9419E80: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942CEB1: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x94353F4: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9435E0E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x66BC95F: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x9420647: g_object_run_dispose (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x65E8C84: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==    by 0x661D3CE: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.32)
==18084==  Block was alloc'd at
==18084==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18084==    by 0x6BF8858: g_malloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10675: g_slice_alloc (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x6C10B28: g_slice_alloc0 (in /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.1)
==18084==    by 0x943E715: g_type_create_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x941F5A7: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x942141F: g_object_new_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x9421798: g_object_new (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5600.1)
==18084==    by 0x538C02B: gnc_tree_view_account_new_with_root (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-gnome-utils.so)
==18084==    by 0x1D67013F: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6707CE: gnc_import_select_account (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==    by 0x1D6774F0: ??? (in /usr/lib/x86_64-linux-gnu/gnucash/gnucash/libgncmod-generic-import.so)
==18084==
sys:1: Warning: instance with invalid (NULL) class pointer
sys:1: Warning: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed