OK FWIW, TBN (paywall) Ryan O'Halloran did a piece on him -
https://buffalonews.com/sports/bills/ryan-ohalloran-bills-rookie-kaiir-elams-mindset-after-deactivation-make-sure-that-didnt-happen-again/article_3d870d90-8146-11ed-a6bb-d7dfb505ba12.html
The implication I take from that is that Elam was benched for performance reasons such that the Bills felt Rhodes was a better choice for the game - not for "breaking a team rule" or some kind of discipline. Of course, you can question whether my belief colors my interpretation and, of course, whether Elam is going to spill the tea if it was a rule violation discipline. But he makes a fairly convincing case for the above.
But, there is something in the article that puzzles me:
My understanding was that Elam played a lot of man in college and not so much zone.