You can see here how artifacts start appearing, but the problem is more acute when moving around the screen. It is impossible to find combinations like this
I think I've found the culprit here. I've made some adjustments and have played a game up to level 34 on both a revA and a revB units, and was not able to reproduce this any longer.
If you're willing, I'd like to send you a build to side load to see if it fixes it for you. Drop me an email at scenicroutegames@gmail.com if you have some time to to try it out.