I was trying to refresh metadata for one episode in my “Continue Watching” queue and clumsily removed it by mistake.
I’ve tried marking the whole show as “watched,” then “unwatched” up to the episode I was at. I’ve tried playing up till the end of the preceding episode, allowing auto-play to start the next episode, then stop.
As a guess I’d say all the marking watched / unwatched has messed up the play history which continue watching uses to build that list.
What I’d suggest is mark the stuff you have watched as watched and leave the rest unwatched. Then just watch the next episode as normal. Once it’s fully watched (passed 90% so plex registers it as played) it should then pop up on the continue watching deck as normal.
You’re right you have to actually watch through the next unwatched episode. I was trying to manipulate the “Continue Watching” queue by just marking and unmarking which episodes were “played” which wasn’t working.