I need help reproducing this. I currently cannot. It might have been fixed in the last month?
As discussed in more detail at https://en.wikipedia.org/wiki/Wikipedia_talk:Notifications#Mistaken_notification_of_reverted_edit.3F there
An editor received a notification for a reversion, but it wasn't their edit which had directly been reverted. Instead, their edit was one of many that had been reverted. Redrose64 explains there that
I imagine that Mild Bill Hiccup used those [history page] radiobuttons to select two non-consecutive edits, then clicked Compare selected revisions, then used the "undo" link at upper right. This doesn't just undo a whole sequence of edits, it also causes a reversion notification to be sent to all non-IP users who made edits in that sequence. This is not new behaviour, but AFAIK has been normal ever since reverts were added to the notifications system.
I've tried to reproduce this at https://en.wikipedia.org/w/index.php?title=User:Quiddity_II/sandbox&action=history but cannot.
If it has been fixed on purpose, I'll let the editors know.
If it has been changed accidentally, and we switch it back,
or, if it is reproducible,
Then the editors there suggest sending an alternate notification message in those circumstances (which we can file a new task for).