This keeps happening and it is so frustrating =( While I'm painting or erasing, either on the diffuse channel or on masks, this happens randomly. Big white squares appear on my textures, sometimes they vanish, sometimes they stay and I can't get rid of them (they appear when I export the texture too!).
I'm attaching a picture so you can see the problem, and I'm using the 2018.2.1 version.
Thanks in advance
Litha