Podcasts show multiple times in iPod Classic

Since the latest update on MacOS (11.4), when I sync my iPod Classic with the computer, the newest podcast episodes are listed nine times, both in the Finder window where I look at my iPod, and in the iPod itself, but it only shows once in the Podcast app on the Mac (see image below). If you play one of these episodes on the iPod, it shows all copies of that podcast playing at once (in the list, they all have the speaker icon next to them). In the iPod, they show as played, but when you re-sync the iPod afterwards, only one of the nine copies will remove itself, leaving eight copies remaining, even though it's now marked as played and deleted from the Podcast app on the Mac. This is very frustrating, and I'd like to fix this. This happened once in the past, and I remember deleting some hidden file somewhere that fixed it, but I didn't bookmark the page where I found the instructions on doing this, and my Google-Fu is failing me on finding it again. Can anyone help?