@jefito
No, as I said, it should warn the user. This gives the user to then do whatever they need to to back up their changes before refreshing. There are of course ways to deal with conflicts (for example, how Git does it), but I'm not saying we need to solve that problem. All I'm asking for is a warning - such a solution would be much better than nothing at all.
I agree that when you are editing it you may not know this, but my point is that upon saving the note, the system can detect this, and not just blindly overwrite the note.
Finally, as far as the "note conflicts" thing, that would be fine (although inferior to the warning, IMO), but it doesn't seem to work, at least in the browser edition.