Ok, if you think it may have to do with a missing note off or a recurrent note on, then, if possible, you should see if you can use a midi monitor app in order to see what the Digitakt is actually sending. If it looks like something unusual then it might be easier to troubleshoot where it’s coming from and should probably behave in a predictable fashion once you pin it down, most bugs are usually only a mystery until you figure out the conditions that bring them on.
Not sure I can help but I’ll see what I can do, and at a minimum if you figure it out then it can be reported and validated for a future fix. Also check out the digitakt II bug reports thread and see if anyone else has already reported something similar, that might also help validate the issue. Good luck to you as well!
And just to be thorough I checked and for both of you this is possibly relevant:
To complete the quote, the tail end of that post says:
“EDIT: I recently got word that the team is aware of this bug, and that it’s being worked on. It’s related to sending notes from an external MIDI controller on the auto channel while switching channels (extremely common if you’re using another sequencer for MIDI input). No word on when that might be in a firmware update.”
So, Sonarman, even on the current firmware if midi is involved this could be the issue. Sounds an awful lot like what you initially described.