Bug#854373: I confirm the bug

[Karl Heisenberg]

I experience the same bug with the latest debian-sid:kwin_x11 5.13.1-1+b1nvidia 
390.77-1
the freeze is about every 1-2 hours, and it takes 1-2 minutes to restart kwin 
since also switching to terminal by ctrl-alt+f1 is delayed.
Very annoying bug...