There could be a few reasons why your played podcasts or episodes are not being marked as played.
1. There is a problem with your network connection, which is preventing the play history from syncing to the server.
2. The local cache on the app has expired, which is causing the play history to not be recorded.
3. It could also be a problem with the podcast app itself.
You can try to troubleshoot the issue by checking your network connection, clearing the cache on the app, or contacting the our support for further assistance.