Thanks for the suggestions-
I am beginning to see why nested sequences are probably best avoided entirely. The problem is that for this project I really need to be able to always edit and change each individual sequence, and see how the changes are reflected in the increasingly complicated master sequence, so in this case I can’t really export and bring them back in or simplify the workflow- I guess I’ll just have to slog through.
I obviously should be using a different program to do this. I don’t know if there are any editing programs that are more stable when dealing with nested sequences.