Offline character lost progress. It doesn’t seem like the game always saves when you Save and Exit. I’m not exactly sure how else to force the game to save.
Edit: I’m guessing the game only actually saves when you see the red spinning icon in the lower right?
If that’s the case then Save and Exit doesn’t always trigger this when it of course should. Trivial to reproduce and witness. The workaround I guess would be doing random things in game until you see it save. Connecting to Battle.net also might trigger it to save.