Yes that is what is happening. What seems to happen is I make a few little changes, and all is well.
It happens when I make a lot of changes. After I finish, I create a snapshot, which changes to an unsaved time period at a point in time during my edits.
I have deleted all snapshots and only have the one I created, and it happens. A reboot fixes it back to the set snapshot until some random time triggers it. Sometimes, it is after waking from sleep, and other times, I can't say.