I’ve had this occurring quite a bit lately. Not sure exactly what the steps are to reproduce because it doesn’t seem consistent, but here’s one way it can happen:
If I’m watching a series on one ATV, shut it down and resume from another ATV, e.g., moving from the lounge to the bedroom, I’ll sometimes get three copies of every episode showing up on the second ATV. Not sure why three copies, but I have three ATVs in the house if that means anything.
 - scratch the bit about changing ATVs. It just happened on the one I was already using, after shutting it down for a while, turning it back on to watch something else with Infuse, then going back to the series I was watching earlier… bam, three copies of everything.
This only happens if I go directly to the season via the ATV top shelf, or via the Watching section on the home screen. If I navigate to the share via Favourites and down into the series folder, it shows the correct number of episodes - I guess because it’s re-scanned the directory on the way in.
There is only one copy of the show on my NAS, and only one share to the NAS per ATV.
Restarting Infuse doesn’t solve this.
Currently running Pro 5.7.4 but it’s happened on previous versions as well.