It turns out that IPP is required for AirPrint to work, so I can't leave that disabled. I re-enabled it (but left Raw/LPR disabled) and the exception reports have started printing again, so it's definitely an IPP problem.
Sorry to revive this old thread, but i have that same issue with my workcenter 3215 that i just bought 1 year ago, printing an exception report every few hours which is wasting so much papers! i have the latest frirmware installed too which dates from 2018 (3.50.03.01). I have beeb trying to fix that issue for may hours now, and disabling airprint is NOT an option for us (sorry...) i cant imagine that Xerox has not released a firmware that fix that issue!! I will wait if i get a reply to this post, if not, i will have to buy a different brand of printer i guess, and will give up on Xerox..
@martinhbs this problem somehow stopped occurring without doing anything that I can recall to fix it ... I definitely didn't disable any protocols, and still have AirPrint enabled. I wish I could help you out, but it's truly a ghost-in-the-machine situation