Episode Does Not End

For awhile now I have had my sister have an issue where the episode she was watching would stay playing at the end of the episode. So on my end (the server) will show her playing the episode, but its 55/55 Minutes. Saying Buffering. As far as I know she finishes and turns everything off. She is using a Chrome browser to pick the episode and stream to the Chromecast.

Now for no reason, after years, my fathers Android device seems to be doing the same thing. He picks the episode with the Android app and streams it to a Chromecast. Same issue. To end this I need to turn the TV on go to the Chromecast, see its still there at the end of the video, reconnect the Plex app to the Chromecast, and hit STOP.

No idea why this is happening, my mothers iPhone does not do this and even my dads Android only started doing it. What is wrong with it?