I suspect the issue I am experiencing is similar to what was reported here:
And perhaps it first occurred to me after I did the same: duplicated a track while plaing the song. Then weird things started happenning:
- Two completely unrelated MIDI tracks suddenly showed some of their parts as grouped: whenever I selected a part on one of those tracks, a part starting at the same time on a different track was also selected.
- Later I saw that three tracks were grouped in such way.
- The only workaround was to change start and enpoints of parts on one of the tracks by first drawing an empty part with a pencil tool and then merging this fake part with another part. Since the new part had a different length it no were longer grouped with a part on another track.
- The workaround (4) worked only as long as parts on “grouped” tracks had different start/endpoints. Once I cut them according to the song structure (so both “grouped” tracks had the same part timing information), parts became grouped again, so any attempt to select a single part resulted in selection of a related part on a different track.
Needless to say that this is quite annoying. I am using Cubase 8.5 on a Windows machine.