[Zubersoft]

I haven't spent an extended amount of time annotating the same score on the Lumi. The problem detailed in this post showed that the problem could be reproduced by just entering the annotation editor, creating a stroke, and then exiting. That seemed like that would either happen for me, or it wouldn't. It didn't seem related to how long the app had been in use, although the John can correct me if I'm wrong about that. 

As far as the issues you are seeing, I haven't seen those yet either, but I can try testing a score for longer and seeing if it happens for me in the bottom 20% of the score. Unfortunately, because I'm jumping between customer support and developing the three different versions (Windows, Android and iOS), I don't really have chances to use the app for long periods of time which may be required to see certain issues. I will run longer tests when needed to track down certain issues, but I generally just test long enough to see if I can reproduce a given issue.

Mike