Update 2 - snapshots stopped again like before a few hours later. This appears to be another reduction in what we get with monitoring subscription. It would be nice if RING were up front with informing customers rather than reducing service silently like this.
Update - reboot via removing and reinstalling the battery restored to normal.
Snapshots stopped working at approximately 1:41 am EDT - no app updates and no changes to app or network. Motion capture working normally. Other cameras on the network snapshots working normally.