In fact, the episode rewinds about 4 minutes and remains showing unwatched.
If you try to manually mark the item as watched, it doesn't work. (typically doing this on Plex on Apple TV)
It also doesn't work trying to mark a watched item as unwatched
If I do it using Plex media Player ( Mac OS X) the I get the error
"There was an unexpected error marking an item as watched"
I've tried doing it form every angle (whole season, on the server, on Apple TV, on iOS etc, same result)
This is getting really annoying- being unable to easily determine which shows are watched or not
Mac OS X 10.13.4