Here’s another low priority difficult to find bug for you.
Every once in a while, I’ll come across a note that cannot be moved into one specific spot on the timeline. When I try to place it there, it instead vertically jumps to a different position, and an unrelated nearby note will also jump. It is only a rendering bug though, as the correct notes sound.
I saved the file so you could inspect it, but when I opened it in a new tab, the bug went away. When I reopened it in the original tab, it was still there, so it has something to do with the state of the web app rather than the file. Unfortunately that means inspecting this file won’t be of much help. I can’t even give you steps to reproduce it because it only occurs deep into a session and I’ve only had it happen maybe a dozen times in the last couple of years.
Here, the highlighted note in measure 44 cannot be an A at the same time the highlighted note in measure 46 is an E. If attempted, by moving the first note down a semitone, they visually swap vertical positions:
From here, moving either note vertically or horizontally causes them to swap back.
The bug appears to go away if I add or delete any previous measures, but if I add a measure and then delete it again, or even add a measure and delete a different one, the bug reappears. It also goes away if I select some random previous measures and change their key, but when I remove the two resulting key changes it again reappears. Changes to future measures don’t seem to affect it.
So yeah. Not super important, just weird. Good luck with this one!