I don't get it, I never get glitches on RDR. Never. Not once. I've been in Private Free Roams with 5+ friends who all experience the same glitch (for example, can't drive Stage-coaches) in Free Roam but I don't. Only few glitches I've had are enemies getting stuck behind geography in Gang Hideouts (therefore rendering unbeatable albeit for the lucky Dynamite strike) or John Marston being launched 200ft in the air when jumping and going into cover at the same time. It's perfect otherwise.
EDIT: I was reminded by an earlier post, once I was in the Train Station and a man was sitting on a bench backwards. It was as if he sat down on the bench and turned a full 180 degrees, as he was sitting on thin air. I got a picture on my phone, but I think it's gone now. Other than those, nothing.