I rescind my earlier comment about the crashes going away. I was doing a bunch of stuff in 8-bit color when I first tried the new version, and didn't think to switch until now. Turns out my crashes only occur in 16-bit color, and with the same frequency across versions. So to anyone else getting (or trying to get!) the level cycle crashes, try changing color depth. So far I've done around 1000 cycles in 8-bit color with animation-heavy levels without a single crash. I'll run a longer test tomorrow but I have to turn off my computer now.

This also gives me a hunch as to the vague nature of what's causing the problem, but any JJ2+ dev reading this already knows what that hunch is .