There's a bunch of reports of this on the error tracker.  Here's the BT from the most recent one (nothing private in there I can see).

Stacktrace

#0  0x00007f5dcd1754a0 in as_store_load_yaml_file (error=0x7ffdd3cfeb40, cancellable=0x0, file=0x55dc2db9a900, store=0x55dc2db4b880) at as-store.c:1135
        tmp = <optimized out>
        ctx = 0x55dc2db8e800
        icon_path = 0x0
        root = 0x55dc2db9be40
        app_n = <optimized out>
        n = <optimized out>
        tok = 0x0
#1  as_store_from_file_internal (store=store@entry=0x55dc2db4b880, file=file@entry=0x55dc2db9a900, id_prefix=id_prefix@entry=0x7f5dcd17e9ae "system", cancellable=cancellable@entry=0x0, error=error@entry=0x7ffdd3cfeb40) at as-store.c:1371
        filename = 0x55dc2db6c890 "/var/lib/app-info/yaml/de.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_Components-amd64.yml.gz"
        icon_prefix = 0x0
        error_local = 0x0
        root = 0x0
        ptask = 0x55dc2db8e870
        __func__ = "as_store_from_file_internal"
#2  0x00007f5dcd175ab7 in as_store_load_app_info_file (error=0x7ffdd3cfeb40, cancellable=0x0, path_xml=0x55dc2dbebb20 "/var/lib/app-info/yaml/de.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_Components-amd64.yml.gz", id_prefix=0x7f5dcd17e9ae "system", store=0x55dc2db4b880) at as-store.c:2068
        file = 0x55dc2db9a900
        ptask = 0x55dc2db8ea90
#3  as_store_load_app_info (store=store@entry=0x55dc2db4b880, id_prefix=id_prefix@entry=0x7f5dcd17e9ae "system", path=path@entry=0x55dc2db57700 "/var/lib/app-info/yaml", flags=flags@entry=AS_STORE_LOAD_FLAG_APP_INFO_SYSTEM, cancellable=cancellable@entry=0x0, error=error@entry=0x7ffdd3cfecd8) at as-store.c:2118
        error_store = 0x0
        filename_md = 0x55dc2dbebb20 "/var/lib/app-info/yaml/de.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_Components-amd64.yml.gz"
        tmp = <optimized out>
        dir = 0x55dc2db6c420
        error_local = 0x0
        tok = 0x55dc2db4b868
#4  0x00007f5dcd176131 in as_store_search_app_info (store=store@entry=0x55dc2db4b880, flags=flags@entry=AS_STORE_LOAD_FLAG_APP_INFO_SYSTEM, id_prefix=id_prefix@entry=0x7f5dcd17e9ae "system", path=path@entry=0x55dc2db4e440 "/var/lib/app-info", cancellable=cancellable@entry=0x0, error=error@entry=0x7ffdd3cfecd8) at as-store.c:2333
        dest = 0x55dc2db57700 "/var/lib/app-info/yaml"
        supported_kinds = {0x7f5dcd180d6d "yaml", 0x7f5dcd17f659 "xmls", 0x0}
        i = <optimized out>
#5  0x00007f5dcd176be4 in as_store_search_per_system (error=<optimized out>, cancellable=0x0, flags=<optimized out>, store=<optimized out>) at as-store.c:2535
        dest1 = 0x55dc2db4e440 "/var/lib/app-info"
        dest2 = 0x0
        data_dirs = 0x55dc2db4e420
        i = <optimized out>
        ptask = 0x55dc2db4e2f0
#6  as_store_load (store=<optimized out>, flags=<optimized out>, cancellable=0x0, error=<optimized out>) at as-store.c:2683
        ptask = 0x55dc2db4e220
        tok = 0x55dc2db4b868
#7  0x000055dc2d1479c7 in main (argc=1, argv=0x7ffdd3cfee98) at fu-main.c:2126
        priv = 0x55dc2db49700
        immediate_exit = 0
        ret = <optimized out>
        timed_exit = 0
        context = 0x55dc2db48af0
        owner_id = 0
        retval = 1
        options = {{long_name = 0x55dc2d157408 "timed-exit", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffdd3cfecd4, description = 0x55dc2d157413 "Exit after a small delay", arg_description = 0x0}, {long_name = 0x55dc2d15742c "immediate-exit", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffdd3cfecd0, description = 0x55dc2d157ab0 "Exit after the engine has loaded", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}
        error = 0x0
        config_file = 0x0
        config = 0x0
Thread Stacktrace

.
Thread 2 (LWP 1639):
#0  0x00007f5dcab45e8d in poll () at ../sysdeps/unix/syscall-template.S:84
No locals.
#1  0x00007f5dcbe5f39c in g_main_context_poll (priority=2147483647, n_fds=2, fds=0x7f5dbc0008c0, timeout=<optimized out>, context=0x55dc2db62d00) at /build/glib2.0-7IO_Yw/glib2.0-2.48.1/./glib/gmain.c:4135
        poll_func = 0x7f5dcbe6e290 <g_poll>
#2  g_main_context_iterate (context=context@entry=0x55dc2db62d00, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/glib2.0-7IO_Yw/glib2.0-2.48.1/./glib/gmain.c:3835
        max_priority = 2147483647
        timeout = -1
        some_ready = <optimized out>
        nfds = 2
        allocated_nfds = 2
        fds = 0x7f5dbc0008c0
#3  0x00007f5dcbe5f4ac in g_main_context_iteration (context=0x55dc2db62d00, may_block=may_block@entry=1) at /build/glib2.0-7IO_Yw/glib2.0-2.48.1/./glib/gmain.c:3901
        retval = <optimized out>
#4  0x00007f5dcbe5f4e9 in glib_worker_main (data=<optimized out>) at /build/glib2.0-7IO_Yw/glib2.0-2.48.1/./glib/gmain.c:5672
No locals.
#5  0x00007f5dcbe85bc5 in g_thread_proxy (data=0x55dc2db4d850) at /build/glib2.0-7IO_Yw/glib2.0-2.48.1/./glib/gthread.c:780
        thread = 0x55dc2db4d850
#6  0x00007f5dcae1b6fa in start_thread (arg=0x7f5dc3cc1700) at pthread_create.c:333
        __res = <optimized out>
        pd = 0x7f5dc3cc1700
        now = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140040693618432, 9010779530266142641, 0, 140728157070879, 140040693619136, 0, -8955619352877471823, -8955638761976895567}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <optimized out>
        pagesize_m1 = <optimized out>
        sp = <optimized out>
        freesize = <optimized out>
        __PRETTY_FUNCTION__ = "start_thread"
#7  0x00007f5dcab51b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109
No locals.
.
Thread 1 (LWP 1635):
#0  0x00007f5dcd1754a0 in as_store_load_yaml_file (error=0x7ffdd3cfeb40, cancellable=0x0, file=0x55dc2db9a900, store=0x55dc2db4b880) at as-store.c:1135
        tmp = <optimized out>
        ctx = 0x55dc2db8e800
        icon_path = 0x0
        root = 0x55dc2db9be40
        app_n = <optimized out>
        n = <optimized out>
        tok = 0x0
#1  as_store_from_file_internal (store=store@entry=0x55dc2db4b880, file=file@entry=0x55dc2db9a900, id_prefix=id_prefix@entry=0x7f5dcd17e9ae "system", cancellable=cancellable@entry=0x0, error=error@entry=0x7ffdd3cfeb40) at as-store.c:1371
        filename = 0x55dc2db6c890 "/var/lib/app-info/yaml/de.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_Components-amd64.yml.gz"
        icon_prefix = 0x0
        error_local = 0x0
        root = 0x0
        ptask = 0x55dc2db8e870
        __func__ = "as_store_from_file_internal"
#2  0x00007f5dcd175ab7 in as_store_load_app_info_file (error=0x7ffdd3cfeb40, cancellable=0x0, path_xml=0x55dc2dbebb20 "/var/lib/app-info/yaml/de.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_Components-amd64.yml.gz", id_prefix=0x7f5dcd17e9ae "system", store=0x55dc2db4b880) at as-store.c:2068
        file = 0x55dc2db9a900
        ptask = 0x55dc2db8ea90
#3  as_store_load_app_info (store=store@entry=0x55dc2db4b880, id_prefix=id_prefix@entry=0x7f5dcd17e9ae "system", path=path@entry=0x55dc2db57700 "/var/lib/app-info/yaml", flags=flags@entry=AS_STORE_LOAD_FLAG_APP_INFO_SYSTEM, cancellable=cancellable@entry=0x0, error=error@entry=0x7ffdd3cfecd8) at as-store.c:2118
        error_store = 0x0
        filename_md = 0x55dc2dbebb20 "/var/lib/app-info/yaml/de.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_Components-amd64.yml.gz"
        tmp = <optimized out>
        dir = 0x55dc2db6c420
        error_local = 0x0
        tok = 0x55dc2db4b868
#4  0x00007f5dcd176131 in as_store_search_app_info (store=store@entry=0x55dc2db4b880, flags=flags@entry=AS_STORE_LOAD_FLAG_APP_INFO_SYSTEM, id_prefix=id_prefix@entry=0x7f5dcd17e9ae "system", path=path@entry=0x55dc2db4e440 "/var/lib/app-info", cancellable=cancellable@entry=0x0, error=error@entry=0x7ffdd3cfecd8) at as-store.c:2333
        dest = 0x55dc2db57700 "/var/lib/app-info/yaml"
        supported_kinds = {0x7f5dcd180d6d "yaml", 0x7f5dcd17f659 "xmls", 0x0}
        i = <optimized out>
#5  0x00007f5dcd176be4 in as_store_search_per_system (error=<optimized out>, cancellable=0x0, flags=<optimized out>, store=<optimized out>) at as-store.c:2535
        dest1 = 0x55dc2db4e440 "/var/lib/app-info"
        dest2 = 0x0
        data_dirs = 0x55dc2db4e420
        i = <optimized out>
        ptask = 0x55dc2db4e2f0
#6  as_store_load (store=<optimized out>, flags=<optimized out>, cancellable=0x0, error=<optimized out>) at as-store.c:2683
        ptask = 0x55dc2db4e220
        tok = 0x55dc2db4b868
#7  0x000055dc2d1479c7 in main (argc=1, argv=0x7ffdd3cfee98) at fu-main.c:2126
        priv = 0x55dc2db49700
        immediate_exit = 0
        ret = <optimized out>
        timed_exit = 0
        context = 0x55dc2db48af0
        owner_id = 0
        retval = 1
        options = {{long_name = 0x55dc2d157408 "timed-exit", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffdd3cfecd4, description = 0x55dc2d157413 "Exit after a small delay", arg_description = 0x0}, {long_name = 0x55dc2d15742c "immediate-exit", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffdd3cfecd0, description = 0x55dc2d157ab0 "Exit after the engine has loaded", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}
        error = 0x0
        config_file = 0x0
        config = 0x0