I could probably wipe my subscription list and see if that resolves this problem, but as I think I have over 200 subscribed items this would be a pretty big pain, but I can provide other troubleshooting information and do any necessary troubleshooting/isolation tests if it would help in diagnosing and/or fixing this.
Is there some sort of local cache of the steam-subscribed workshop items that I could clear that would be restored so I wouldn't have to remove all my subscriptions? I tried searching around for a workshop troubleshooting guide but couldn't find one unfortunately.