If you happen to have two kegs and a few empty bottles for the next time, it would be a good experiment to do all three processes (Keg with starsan, bottle & keg with iodophor) in parallel with the same fermented beer. Yeah probably too much fuss, but seeing that you are trouble shooting to find something that is driving you crazy, you might try it.
I'd be interested to follow along. Good luck.
I'd be interested to follow along. Good luck.