iTunes Podcast Subscribed Button locked off
I recently had problems syncing iTunes Podcasts from an iMac to an iPhone and iPad. A duplicate subscription had crept in as well. I deleted the Apple Podcast app from the iPhone and iPad, then deleted and reloaded the iTunes Podcast subscriptions on the iMac. Having then reloaded the Apple Podcast app to the two devices all appeared to be OK there.
However on the iMac/iTunes two of the Podcasts are showing as Not Subscribed and do not allow me to change their status via the settings sprocket/button - the Subscribed button is set to OFF with a small lock symbol within the button and none of the settings can be changed. They are current podcasts [one is Kermode & Mayo’s Film Review] and previously were updating OK.
I can’t find any help for this in Support so wonder if anyone has advice? Many thanks.
macOS High Sierra 10.13.2
iTunes 12.7.2.58
iMac with Retina 5K display, macOS High Sierra (10.13.1)