Podcast Sync Issues - iTunes 12.7 and iOS 11
I'm posting this in the hope it will help others if they experience issues similar to mine following the recent updates to iTunes (v12.7) and iOS 11.
Issues:
1 - Locked Subscribe button (padlock) in iTunes Podcasts Settings.
2 - Syncing downloaded episodes via iTunes can duplicate those episodes on the iDevice.
3 - Syncing downloaded episodes via iTunes doesn't always remove the "cloud" icon, possibly connected to 2.
4 - Episodes played on one device not showing as such on others.
For 1 I've found that ctrl clicking on the Podcast show title and selecting "Delete from Library" appears to remove the padlock. You might get a warning regarding several podcasts but you can still download afterwards if required.
In the above you would ctrl click on "MacCast....."
You may need to turn the Subscribe button on/off or off/on to get the desired setting back.
For 2, 3 and 4 you need to remove all Podcast information from you iDevices and let it come back down from the Apple. The easiest way is to go into Settings/General/iPhone or iPad Storage and scroll down to Podcasts, when in Podcasts click "Delete App".
This removes the app and all it's data (which includes any stored episodes), once done you can then go to the App Store and download the Podcasts App again.
Depending on if you require the app or iTunes to manage the episodes you might need to go into Podcast Setting (Settings/Podcasts) and set the "Download Episodes" to Off, Only New or All Unplayed - it can be Off if you intend to manage via iTunes.
Hopefully, clearing out data on the iDevices also removes any possible conflicts with what Apple has stored (which may have come about from iTunes or previous iOS updates.
The above is what I've found works for me, the logic might stand being corrected by those that have a better understanding on how the whole syncing process works between iTunes, Apple and our iDevices, but until Apple decides to give us a method to simply Reset the whole Podcast process it will have to do (or does that already exist?).
iMac (21.5-inch, Late 2013), macOS High Sierra (10.13), 500Gb SSD, 3.1GHz i7