It’s generally much easier to diagnose these kinds of problems if you attach the project here. You’ll score extra brownie points if you also cut the project down to just the affected instrument(s) and ideally the affected bars. Then we can simply open it up and investigate the problem right away without needing to go hunting around for the problem. Also, cutting the project down can sometimes reveal something about what’s causing the problem, as you might find that having deleted some bars, the problem no longer occurs.
I hope you won’t mind me posting a link to our general advice about how to seek help with these kinds of problems: