Wayland session crashed (and the system went to login screen) two times today on my neon dev unstable.
first time crashed when I moved VLC player window during video playback using the touch screen. Second time crashed when I "clicked" the seek bar of smplayer using the touch screen during video playback.

#0  malloc_consolidate (av=av@entry=0x7f9f2e719b20 <main_arena>) at malloc.c:4175
#1  0x00007f9f2e3d6cde in _int_malloc (av=av@entry=0x7f9f2e719b20 <main_arena>, bytes=bytes@entry=4096)
    at malloc.c:3450
#2  0x00007f9f2e3d9184 in __GI___libc_malloc (bytes=bytes@entry=4096) at malloc.c:2913
#3  0x00007f9f2e3c21d5 in __GI__IO_file_doallocate (fp=0x7f9f2e71a620 <_IO_2_1_stdout_>)
    at filedoalloc.c:127
#4  0x00007f9f2e3d0594 in __GI__IO_doallocbuf (fp=fp@entry=0x7f9f2e71a620 <_IO_2_1_stdout_>)
    at genops.c:398
#5  0x00007f9f2e3cf8f8 in _IO_new_file_overflow (f=0x7f9f2e71a620 <_IO_2_1_stdout_>, ch=-1)
    at fileops.c:820
#6  0x00007f9f2e3ce28d in _IO_new_file_xsputn (f=0x7f9f2e71a620 <_IO_2_1_stdout_>, 
    data=0x7f9f2fffac2e, n=10) at fileops.c:1331
#7  0x00007f9f2e3a2241 in _IO_vfprintf_internal (s=0x7f9f2e71a620 <_IO_2_1_stdout_>, 
    format=0x7f9f2fffac2e "sock_file=%s\n", ap=ap@entry=0x7fff7dd8edf8) at vfprintf.c:1320
#8  0x00007f9f2e46b9ef in ___printf_chk (flag=1, format=<optimized out>) at printf_chk.c:35
#9  0x00007f9f2fff8579 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5Crash.so.5
#10 0x00007f9f2fff89db in ?? () from /usr/lib/x86_64-linux-gnu/libKF5Crash.so.5
#11 0x00007f9f2fff91e9 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5Crash.so.5
#12 0x00007f9f2fff93f3 in KCrash::defaultCrashHandler(int) ()
   from /usr/lib/x86_64-linux-gnu/libKF5Crash.so.5
#13 <signal handler called>
#14 0x00007f9f1e0a15b9 in wl_map_insert_at (map=<optimized out>, flags=flags@entry=0, 
    i=<optimized out>, data=<optimized out>) at ../src/wayland-util.c:249
#15 0x00007f9f1e09d7be in proxy_destroy (proxy=0x260fda0) at ../src/wayland-client.c:411
#16 wl_proxy_destroy (proxy=proxy@entry=0x260fda0) at ../src/wayland-client.c:442
---Type <return> to continue, or q <return> to quit---
#17 0x00007f9f1c84afd7 in org_kde_plasma_window_destroy (org_kde_plasma_window=0x260fda0)
    at /workspace/build/obj-x86_64-linux-gnu/src/client/wayland-plasma-window-management-client-protocol.h:642
#18 KWayland::Client::WaylandPointer<org_kde_plasma_window, org_kde_plasma_window_destroy>::release (
    this=0x26242a0, this=0x26242a0) at /workspace/build/src/client/wayland_pointer_p.h:53
#19 KWayland::Client::PlasmaWindow::release (this=this@entry=0x24ee1d0)
    at /workspace/build/src/client/plasmawindowmanagement.cpp:757
#20 0x00007f9f1c84affa in KWayland::Client::PlasmaWindow::~PlasmaWindow (this=0x24ee1d0, 
    __in_chrg=<optimized out>) at /workspace/build/src/client/plasmawindowmanagement.cpp:747
#21 0x00007f9f1c84b0e9 in KWayland::Client::PlasmaWindow::~PlasmaWindow (this=0x24ee1d0, 
    __in_chrg=<optimized out>) at /workspace/build/src/client/plasmawindowmanagement.cpp:748
#22 0x00007f9f2e9b9703 in QObjectPrivate::deleteChildren (this=this@entry=0x252c190)
    at kernel/qobject.cpp:1997
#23 0x00007f9f2e9c37f4 in QObject::~QObject (this=<optimized out>, __in_chrg=<optimized out>)
    at kernel/qobject.cpp:1025
#24 0x00007f9f1c84b699 in KWayland::Client::PlasmaWindowManagement::~PlasmaWindowManagement (
    this=0x25c0b40, __in_chrg=<optimized out>)
    at /workspace/build/src/client/plasmawindowmanagement.cpp:254





#25 0x00007f9f2e9b9703 in QObjectPrivate::deleteChildren (this=this@entry=0x252b9a0)
    at kernel/qobject.cpp:1997
#26 0x00007f9f2e9c37f4 in QObject::~QObject (this=<optimized out>, __in_chrg=<optimized out>)
    at kernel/qobject.cpp:1025
#27 0x00007f9eef7676a3 in WaylandIntegration::~WaylandIntegration (this=<optimized out>, 
    __in_chrg=<optimized out>) at /workspace/build/src/windowsystem/waylandintegration.cpp:54
#28 WaylandIntegrationSingleton::~WaylandIntegrationSingleton (this=<optimized out>, 
---Type <return> to continue, or q <return> to quit---
    __in_chrg=<optimized out>) at /workspace/build/src/windowsystem/waylandintegration.cpp:40
#29 (anonymous namespace)::Q_QGS_privateWaylandIntegrationSelf::Holder::~Holder (this=<optimized out>, 
    __in_chrg=<optimized out>) at /workspace/build/src/windowsystem/waylandintegration.cpp:46
#30 0x00007f9f2e38eff8 in __run_exit_handlers (status=0, listp=0x7f9f2e7195f8 <__exit_funcs>, 
    run_list_atexit=run_list_atexit@entry=true) at exit.c:82
#31 0x00007f9f2e38f045 in __GI_exit (status=<optimized out>) at exit.c:104
#32 0x0000000000408670 in ?? ()
#33 0x00000000004054a7 in ?? ()
#34 0x00007f9f2e375830 in __libc_start_main (main=0x404600, argc=5, argv=0x7fff7dd92e58, 
    init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff7dd92e48)
    at ../csu/libc-start.c:291
#35 0x0000000000405c69 in _start ()