Oh, I see what you mean. I've had a similar bug with painter 12 on mac os, and yes, it also has been happening mostly on 150 % zoom level
the worst part is that it appeared in painter 12 as a purely UI/rendering issue, but sometimes it would smh damage the canvas and leave really thin lines of oversaturated color, that would be visible in the other packages
anyway I haven't seen it since upgrading to 12.2 and resetting my workspace (make sure you back-up your custom brushes/papers/etc first, and don't export your workspace if you see some bugs with it - those would most likely be exported as well), so either corel fixed it or resetting workspace helped in my case.