Is there a way you could role back the save a few hours or something like that?

Yep, same issue. Both the board's name and the content on it are gone. Originally thought the missing content was a "camera" issue i.e. the elements no longer being within the current frame until i came across this and noticed that the name of the board was gone too, just like @ThatGuyObi described.

My whiteboards are not saving either and I don't even see a manual save option. Hours of work on a family tree gone. Twice! First time the whole whiteboard was blank, even the name of the Whiteboard gone. Second time it saved the name of the whiteboard and 1 character name.