Podcast Subscribe not working - button active but nothing happens when clicked - iTunes 12.2.0.145

Do Apple even look at the podcast functionality in iTunes and iOS anymore? I'm starting to wonder if they're intentionally marginalising podcast listeners with each new release.

I have a LOT of podcasts in my library and suddenly I seem to have been randomly unsubscribed from a majority of the ones I had previously been subscribed to. Not only that but when I go to subscribe to them again - either through the Subscribe button at the bottom right of the window or through the right-click context menu - nothing happens. The button shows the visual feedback of the button getting clicked but it doesn't change the button to Unsubscribe nor does it activate the Settings... button for that podcast. This means that I have to expand the list of episodes for all my subscribed podcasts to see if there are any episodes that haven't been downloaded and manually set them to download.

Is this a known issue or is there a workaround? As a committed podcast listener, I feel a little like I'm in an abusive relationship with Apple, continually eating away at the small amount of decent functionality they may have had in previous versions.