[KDE] since 5.16 - spectacle freezes system

[cluster]

since the 5.16 update spectacle freezes the whole system so I have to use a hard reset ...
the spectacle notification dialog box suddenly pops up on the left instead of the right and then the system (mouse, keyboard) freezes.
I use a 3 screen setup w/ nvidia-dkms-415.

[Snowhog]

Rather than resorting to a power-off/power-on approach, you should see if using the Magic SysRq key sequence will 'safely' shutdown and reboot your PC.

Added:

My KDE neon User Edition was just upgraded this morning to 5.16. Here, Spectacle works just fine; I used in fact to take two snapshots. Spectacle Version 19.04.2

[jlittle]

Rather than resorting to a power-off/power-on approach, you should see if using the Magic SysRq key sequence will 'safely' shutdown and reboot your PC.

Also, you might try getting a Linux console with Ctrl-Alt-F2. If you get the login prompt, you can login and do 'sudo reboot'. Enabling the "key sequence to kill the X server" in system settings, input devices, keyboard, and the advanced tab might help.