Starting to narrow down when it happens. Seems more likely when I have my friction levels high. A dropping block comes down on one side of a bunch of touching blocks and the whole bunch goes kabamn and rotates up around the block that just hit them (kinda like a see saw). With lower friction levels I’m still seeing it but significantly reduced.
It seems to happen without control impulses applied.
Difficult to describe and my simple stacking brick test level doesn’t exhibit the same problem.