I had one mule deer years ago that I shot in the peak of the rut - could smell him from 50 yards away as we walked up to him. Buddy with me commented on the stench. It was a clean shot - took one step and went down, gutted on the spot, plenty cold with snow and I took care of him myself like I do all of them. Tried my damndest to eat it but was just nasty all the way. Fed some to the dogs and ended up tossing the rest prior to the next season. I shoot plenty of rutting mule deer that have a stronger flavor and with creative brines and seasoning, am always able to enjoy it. I think sometimes you just get a nasty one and can't explain it...