Lots to pick up on here, but since it’s all specific to Track Archives I wonder if this should be in a dedicated thread - maybe the one in issues?
But for the moment - reliably forcing errors is tricky, but it sure happens sooner or later. Opening archives into different projects is a good start to causing trouble. And it does almost seem related to time - stuff that was created yesterday tends to open nicely, stuff from 3 months ago far less so. Essentially a nightmare to debug…