I don't know a thing about a mule deer but a White-tail is a confounding, unpredictable but predictable contradiction of animal behavior. Around my location the hunting season is long and they get educated very quickly. You may hunt a buck, learn his patterns, pay attention to the wind, scents, etc and only catch him on camera while a 12yo on the next property, playing video games in a stand, being loud and smelling like a whore house kills him the first time he sits.
They're agressive during the rut but gather up again after it. Does stay in groups year round.