From @Neurrone

Extracted from #26730 (comment)

I've restarted NVDA with all add-ons disabled and am still encountering this. I'm experimenting with the read-only settings file and the user settings file.

Am just pressing the left/right arrow keys (arrows, ctrl + left/right arrow to move by word, etc). Notice this especially when you go right/left, then change direction.

Not sure what alt+f1 says, since i can't find the message with NVDA.