I had that happen once, long ago though. Seems like it just happens at random, though I haven't encountered it in years at this point. I might've been mucking around with settings too much and crashed the display driver which then caused that to happen (just once though). Are you on latest drivers? what video card is it?

I got AMD Radeon R9 200 series, drivers up to date.

I was not able to reproduce that issue with the latest development branch and release candidate.

But at one point I was able to notice these shadowed squares in the game long time ago (>1,5 years).

Hello,

are you still experiencing this issue? I had no luck trying to reproduce it.

Thanks