Here,  it crashed again, I was able to acquire a full backtrace this time:
#0  0x00007fa9f9c1dc97 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007fa9f44f2180 in pa_threaded_mainloop_wait () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
No symbol table info available.
#2  0x00007fa9e2fb8732 in pulse_driver_play () from /usr/lib/x86_64-linux-gnu/libcanberra-0.30/libcanberra-pulse.so
No symbol table info available.
#3  0x00007fa9f82de98e in ca_context_play_full () from /usr/lib/x86_64-linux-gnu/libcanberra.so.0
No symbol table info available.
#4  0x00007fa9f82ded0f in ca_context_play () from /usr/lib/x86_64-linux-gnu/libcanberra.so.0
No symbol table info available.
#5  0x00007fa9fab6dcbc in workspace_switch_sound (to=0x1af49d0, from=0x1af4940) at core/workspace.c:496
        layout = {rows = 1, cols = 4, grid = 0x284df50, grid_area = 4, current_row = 0, current_col = 0}
        i = <optimized out>
        y = <optimized out>
        e = 0x7fa9fab9b317 "desktop-switch-right"
        nw = <optimized out>
        x = <optimized out>
        fi = 0
        ti = 1
#6  meta_workspace_activate_with_focus (workspace=0x1af49d0, focus_this=0x0, timestamp=284824597) at core/workspace.c:551
        old = <optimized out>
        move_window = <optimized out>
        screen = <optimized out>
        display = <optimized out>
        comp = <optimized out>
        layout1 = {rows = 13778784, cols = 0, grid = 0xa0, grid_area = -88532346, current_row = 32681, current_col = -88832856}
        layout2 = {rows = 1, cols = 4, grid = 0x284df50, grid_area = 4, current_row = 0, current_col = 0}
        num_workspaces = <optimized out>
        current_space = <optimized out>
        new_space = <optimized out>
        direction = <optimized out>
#7  0x00007fa9fab48b81 in process_event (bindings=<optimized out>, n_bindings=<optimized out>, display=display@entry=0x1d325d0, screen=screen@entry=0xcfb200, window=window@entry=0x0, 
    event=event@entry=0x7fffb68993d0, on_window=0, keysym=<optimized out>) at core/keybindings.c:1441
        handler = 0x1d32e00
        i = <optimized out>
#8  0x00007fa9fab49bd4 in meta_display_process_key_event (display=display@entry=0x1d325d0, window=window@entry=0x0, event=event@entry=0x7fffb68993d0) at core/keybindings.c:1683
        keysym = <optimized out>
        keep_grab = 1
        all_keys_grabbed = <optimized out>
        str = <optimized out>
        screen = 0xcfb200
        __PRETTY_FUNCTION__ = "meta_display_process_key_event"
#9  0x00007fa9fab3e1ab in event_callback (event=0x7fffb68993d0, data=0x1d325d0) at core/display.c:1799
        window = <optimized out>
        property_for_window = <optimized out>
        display = 0x1d325d0
        frame_was_receiver = 0
        bypass_compositor = 0
        filter_out_event = <optimized out>
#10 0x00007fa9fab88ed6 in filter_func (xevent=0x7fffb68993d0, event=<optimized out>, data=<optimized out>) at ui/ui.c:238
No locals.
#11 0x00007fa9f5842921 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
No symbol table info available.
#12 0x00007fa9f5842af7 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
No symbol table info available.
#13 0x00007fa9f5818511 in gdk_display_get_event () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
No symbol table info available.
#14 0x00007fa9f5842832 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
No symbol table info available.
#15 0x00007fa9f9e76a95 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#16 0x00007fa9f9e76dc8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#17 0x00007fa9f9e771c2 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#18 0x00007fa9fab4c257 in meta_run () at core/main.c:555
        log_domains = {0x0, 0x7fa9fab93a6d "muffin", 0x7fa9fab92dab "Gtk", 0x7fa9fab92daf "Gdk", 0x7fa9fab92db3 "GLib", 0x7fa9fab92db8 "Pango", 0x7fa9fab92dbe "GLib-GObject", 
          0x7fa9fab92dcb "GThread"}
        i = <optimized out>
#19 0x0000000000401773 in main (argc=1, argv=0x7fffb68997c8) at main.c:296
        ctx = <optimized out>
        error = 0x0
        ecode = <optimized out>
Detaching from program: /usr/bin/cinnamon, process 4045