Hello,
when starting a long trill over several notes in a uni-son passage, which becomes a divisi-passage in the next line (but is still uni-son for a few bars), the trill will only appear in the upper system.
Best regards
Yes, unfortunately this is the case for a number of ongoing lines crossing into a unison passage. This is something that we plan to address in future versions, though it’s not a simple thing to fix. Thanks for taking the time to report the problem.