The app saves the editing note when opening another note, but it is randomly not working in your setup, which sounds significantly strange.
It also saves when the app loses focus.
The app tries its best not to lose your work.
I suspect one of the installed plugins is causing it, since it happens randomly.
I have never had such an issue, even though I use it every day.
I touched another note it synced an old version over all my changes
What does your revision history of the note look like? You can check old revisions:
Also, if you’re interested, please try the v6 canary version: