Podcasts - Marking all episodes as played

Hi all. I’m giving the stock Apple Podcasts app another shot as I’m trying to reduce my reoccurring subscriptions. I’ve uninstalled my go to podcast app (Pocket Casts) in the hopes of forcing myself to use Apple Podcasts. I’m pretty up to date on most of my podcasts, so I’d like to mark shows as read so I’m not re-listening to old content. I’ve imported all my podcasts in, but on some shows I can mark all the episodes as played and others I cannot. Anyone know why?