Infuse doesn’t have a crystal ball to know how many episodes there are in all tv shows or if there will be more produced. It has to reference what files are available each time you play one of a series. You play the last that infuse sees then it clears the watching list.
Think of how much memory it would take to track ALL of the series you had watched just in case there is a new episode released in the future.
Also as a beta tester you might want to check out the planned upcoming features in “Upcoming Features” thread Upcoming Features (updated 5/7/25)
Note the “Watchlist” feature. 