In the current version of Plex for iOS (and other clients?) there is no way to select to watch a single specific episode of a TV show, as it always automatically generates a play queue for all subsequent episodes of that show.
In an earlier version it used to work such that pressing play on the episode from the season screen would set up the play queue, but drilling down to the episode information screen and pressing play there would just play the selected episode. This meant you could have it play exactly how you wanted, everyone’s happy. Now it creates the play queue from both screens, so if you want to watch a single episode you have to open up the play queue and delete subsequent episodes, missing a chunk of the start of the episode in the process.
I would like to see the earlier behaviour restored.
I’d managed to avoid the issue on my phone until now by staying on an older version of the app. Unfortunately my phone managed to update the Plex app against my will today, so now I need the good people at Plex to fix the current version.