I wrote a note on android version, and did not sync instantly.
then I go to PC version, and make some other changes ,and sync to server.
at last I back to android version and sync to server. then, notes disappeared,have been wiped empty.

I have meet this same issue two times.
and on the other side of coin, I also meet similar issue. I wrote a note on PC version when my PC is offline.
then I make some change on the same Note on Android and sync to server.
at last PC version also sync to server. then, notes only remain the Android version.

I think the version control of Notes is very important.
One day, I input about 9 thousand words into Notes on Android,finally it disappeared after delay sync process. 
Hope this will be payed more attention 
didn't know why this issue has been ignored. is this extremely case and no need to notice? or has been reported before ?

Synchronization of your Brain is very time sensitive. The most important rule to remember is that each individual Thought will default to the most recent change.  This means that if I edit a Thought note on Machine A on Monday (does not matter if it's a desktop, iOS, Android, etc.) and I don't sync.  Then, I edit the same note from Machine B on Tuesday, and again, I don't sync.  When I finally sync ALL machines on Wednesday, only the Machine B, Tuesday edits will exist on this specific note. TheBrain sees that the Tuesday edits are the most recent, so it overrides any previous edits.

Therefore, it's a great idea to set your Brains to auto sync on the desktop. On mobile devices, you'll need to remember to tap the sync button often.  Auto sync for mobile devices is on our feature request list.

Thank you,
What I don't understand, Matt, is why the note would disappear entirely if all ascetic did was edit it on both machines.

Any theories?
Matt,thx your statement

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