Deleted podcasts reappear in sync view

I use iTunes 12.1.2.27 to sync podcasts with my iPhone 6 (iOS 8.3). In the sync view (where I can choose which podcast episode to sync), 27 podcasts I deleted in 2013 are still coming up. There is no trace of them elsewhere, neither on my hard drive, or elsewhere in iTunes, except for in the stream of available episodes.

Does anyone know what the problem is?

Using the automatic sync is not an option for me, as my iPhone is almost full, I would like to choose what podcast episodes to keep on my iPhone and because manual sync'ing is the only way to actually stay in control of what is on my iPhone.