Ok, here is what I did, copy-pasted a macro, removed wire lines, removed the little colored group boxes.
Saved.
Tried to load…
Crashes 100% of the time.
Things that were odd and may possibly related:
Wire points were not connected to the wires when I copy-pasted a macro. This left me with floating wire points. This is fine until I re-did the wire, at which point I suspect they were REALLY orphaned. Saved fine but when I reloaded the file it will crash wm2 every time.