I tried this a few times yesterday, wasn’t able to reproduce the bug i.e. didn’t lose anything but it makes me wonder.
Could it be the case that the autosave (spinning pentagram in bottom right corner) and the manual save from save and exit actually do somewhat different things? For example, if the autosave is strictly local but the manual save also syncs your save with Blizzard servers then if you save and exit in the middle of an autosave the local and cloud saves go off-sync in which case the game very stupidly overwrites your local save with the cloudsave?
I would like to try manually saving in the middle of an autosave to test it but I’m somewhat worried that I’ll end up losing more than a few items in the stash…