[palosanto]

So I have an Onyx Lumi now, but I can't reproduce this issue. It seems to work fine for me every time regardless of whether I use a three-finger tap or not. Can you long press the song you are testing with, tap Share->Export as .msf and send that to mike@zubersoft.com? I can then at least rule out the problem being related in some way to the underlying file. I'm not sure what else to check.

Have you tried working continuously on a score for a while, not just for a few seconds trying to reproduce the issue?
Usually it doesn't happen right away but after a while.

I can confirm this behavior.  At least in my case it only happens at the bottom of the score. Again, it seem to happen randomly (unless it's triggered by a certain sequence of actions which I've tried to reproduce for weeks now ...)

1.- Using the freehand pen or adding a stamp often won't respond at the first or second attempts.
2.- Once is placed, changing tools or exiting annotation mode makes the symbol disappear completely or partially (for pen tool strokes)

Mike, we dealt with these kind of problems many times on these particular area of the screen, I'm sure you remember.  I never had any problems on the top 80-90% of the screen, it's always at the bottom.

I'll shoot a video at the first chance I have to see it happening.