Unrelated parts on different MIDI tracks are grouped forever

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:

  1. 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.
  2. Later I saw that three tracks were grouped in such way.
  3. 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.
  4. 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.

A little update: I created a new track and recorded some MIDI into it. Then suddenly it became grouped with one of old “infected” tracks and attempt to select a part in it resulted in multi-part selection on different tracks. This is really viral!

damn thing is doing this to me too!