I had a real problem getting my head round similar strange behaviour. I even opened a support ticket and sent a video of the issues. Support found the problem - which was user error ?♂️
In my case here is what I was doing wrong;
I created a new performance and started editing.
Then saved it and got random nonsense.
It turns out I was missing one vital step.
I hadn’t double clicked the newly created performance to load it in the edit buffer. I had a assumed that the by creating a performance it would automatically also be loaded into an edit state but this needs to be done manually. You can tell if you are ready to edit as the screen on the KPA itself will show “LIB”. If it doesn’t show this you aren’t ready to edit and chaos will follow.
This is just what happened in my own personal case. You may already be doing this correctly and may have a different issue but I mention it just in case.