I can confirm this bug, also using nvidia proprietary drivers. However, if I don't restart plasma as soon as the corruptions start to appear, I will eventually also lose text in console windows, i.e. text in a certain color will
simply not be printed on the screen (not even on redraw forced by marking and unmarking the area). So I would guess that this is a bug either in plasma or even in qt.
I can confirm this bug, also using nvidia proprietary drivers. However, if I don't restart plasma as soon as the corruptions start to appear, I will eventually also lose text in console windows, i.e. text in a certain color will
simply not be printed on the screen (not even on redraw forced by marking and unmarking the area). So I would guess that this is a bug either in plasma or even in qt.