Most of that work was done 2016 - 2020. Typically we saw issues when people jumped on new features in new releases, so it's pretty much excusable and we'd just forbid the use of these features as long as we didn't really need them.

However, it was not uncommon. I always had a debug build of KiCad on my machine in order to replicate crashes or odd behavior others saw.

It should be noted that we're generally talking about PCBs that could get pretty big and complicated. We certainly uncovered edge cases that were hard to foresee that way.

Curious how big/complicated. I've never done anything more that 6 layers with ~200 cmpts placed in Kicad before.