OK, thanks. Bug reporting by private correspondence it is then! Done. For info of forum users, here is how I can consistently reproduce the problem. Perhaps someone else will see if it happens for you too!
Using V6.1.22. with ALSA sequencer.
Create new project, create new midi track. With 1/4 snap on, draw a region on bar 2 and draw a note on beat 1 of the region.
Turn snap off, grab and drag region start to somewhere before bar 2 start. Turn snap back on and grab region start and drag back to start of bar 2.
The note disappears.
EDITED TO ADD WORKAROUND
FYI, the V6 workaround that's doing it for me is: drag the region start so the note is visible, use the start note quantise function (ALT+5), snap the region start back again.
Using V6.1.22. with ALSA sequencer.
Create new project, create new midi track. With 1/4 snap on, draw a region on bar 2 and draw a note on beat 1 of the region.
Turn snap off, grab and drag region start to somewhere before bar 2 start. Turn snap back on and grab region start and drag back to start of bar 2.
The note disappears.
EDITED TO ADD WORKAROUND
FYI, the V6 workaround that's doing it for me is: drag the region start so the note is visible, use the start note quantise function (ALT+5), snap the region start back again.