not remembering played episodes is happening with me too.
it is very frustrating, especially with podcast that have hundreds of episodes.
open the podcast app and there is 800 or 900 unplayed episodes !!.
not just that, even when i play an episode then delete it, it will come back as unplayed.
another thing, when i sync or transfer podcasts not all of them will transfer to the computer or the iphone.
this is very frustrating and i have not seen any progress or any thing solved in the updates.
I am also having problems with 100s of played podcasts being listed. Like others, if I delete a podcast, it reappears as unplayed the next time I open podcast app in a WiFi zone. In the meantime, the app stops working while it tries to handle all the new info. Finally for some podcasts, it plays and old episode when I select the most recent. I keep selecting "Mark all as played" only to see 100s show up a few hours later. I would prefer played episodes not to be listed in menu at all!
I listen to podcasts on the subway without any ability to stream and prefer to access only from my phone and not have to fuss with computer.
I have read that if you delete the app to go back to using Music app, you can no longer download new podcasts but must do in iTunes. Is there any fix or workaround?