I built a latch mechanism and animated it using joints so it closed in 0 to 45 frames. I then replicated this latch mechanism in six separate building block models. They all worked as planned. I then assembled a structure using XRefs of the building blocks latching into one another in sequence, spacing them out in the timeline so they were synchronized. It worked exactly as planned. Then I saved the project and closed it. The next day I opened the project to set up some camera moves and discovered the XRefs had moved on the timeline so they all started at the same point - from 0 to 45 frames - and not spaced out and synchronized any longer.
I used XRefs because the building blocks were being revised and updated at the same time the assembly project was being developed. The blocks are used multiple times in the same sequence, and I wanted to avoid refreshing multiple models multiple times during development, and I thought that’s what XRefs were for.
I also thought I could use the XRefs like actors, and bring them in and out as needed. Sort of like an Instance. But it appears the XRefs default back to their own individual timelines, not the timeline they are imported into.
Or am I missing something fundamental?
Unfortunately I can’t share the project due to confidentiality. So the description is all I can offer.