parts getting unwanted joined/grouped - please help?

I have an issue where an audio or midi part gets grouped or joined with another on a different track, so that when I select one, both are selected.

I think it happens when I duplicate a track with events on it.

I have tried ungrouping the joined parts. no joy.
saving the project as a back up and reloading doesn’t help either.

Is this a bug related to duplicating tracks?

Am I missing something?

please help? thanks

edits:

one workaround: I exported all the offending tracks. deleted them and the folder they were in. and re-imported. seems to have worked, so far.

Also, it seems I can avoid this issue by moving all events from a track elsewhere before I duplicate it, then moving them back.