I've had this issue recently, I first noticed it a couple weeks ago, after the latest iOS update
If my network connection gets interrupted, the iPhone errors that file, and won't restart it.
Today I started to sync, realized I was on my 2.4 network, so switched to the 5 to make it faster. That locked up 3 shows.
Shows show as converted and waiting to download on the server.
Hit sync on the phone, it "updates information" but nothing happens. Shows are marked as error.
My shows are all sync "unwatched only" I've gotten this to fix itself by marking a show as all watched, syncing on the phone, I can then re-mark the episodes I need to as unwatched, and syncing will start to work again.
The only other post I found about this is in response to one I started, with a disk full error, that also wouldn't automatically clear itself. (And that topic is now giving me a pop-up every 5 seconds that I have answers waiting to be accepted/rejected - - I"m really not a fan of the new-ish forum layout and it's need to provide positive re-inforcement, hopefully I can get a participation trophy.)
Server - Version 1.0.2.2413 -- Ubuntu 64bit (also on 1.0.1, maybe 1.0.0 too)
iOS client. 4.2 - iPhone 6 running iOS 10 public beta#2 (also happened on iOS 9 before the beta came out)
Can we please get a force re-sync button, both for an individual items, and the whole list.
Even if I had to re-encode the media, at least it would work