Downloaded podcast episodes dissapeared

I have had this happen a few times now. There is one podcast that I have subscribed to. I was currently behind and listening to episodes from back in August. There is a new episode added everyday Monday - Friday. I have the settings set to Download all unplayed, Delete played episodes on, Limit episodes off. All of the episodes were downloaded but the other day when I went to the podcast app all of the older episodes that I had not yet listened to were gone. This includes episodes that I had saved. Why is this happening? Is there any way I can go back and add these episodes? They are not showing up in the see all episodes view either.

Thanks