A few weeks ago I started seeing a strange problem on two remote PCs in different locations, built from different components that run Linux Mint 18.2 with KDE 5. Both use Nvidia GPUs, one has an Intel processor and uses it's IGPU for desktop, the other has a Ryzen processor and uses Nvidia or display.

Some Windows randomly stop redrawing. They will redraw if I move them around the screen, but as soon as I stop moving them, they'll freeze again. The only way to get the program to work back again is restarting it. Programs seem to recieve keyboard input and respond o it, but can't refresh their windows.

Most often this causes my Plasma Panel to not refresh, and flip between two frames back and forth in a glitched-out manner.

Other programs that are affected are: Ardour, Firefox and LMMS (happened once so far). I didn't have that happen to Blender or Inkscape (and I use these a lot too). So there is clearly something that relates to the way the application handles display, and if it's affected.

The problems started in similar time period on two machines, so I suspect a recent update must have broken something. I keep both systems updated almost daily, but the problem persists on both machines.

The strangest thing is if I move the affected window around the screen it'll refresh for every frame that it's position changed.

I work a lot in Ardour with 2 windows (Editor and Mixer) opened - often one will be affected, but not the other, no real rule which one and when however, this seems completely random.

PS: I've reported this problem on Linux Mint forums first but maybe this is a better place. (here's the original post: https://forums.linuxmint.com/viewtopic.php?f=56&t=255375&p=1376381#p1376381 )