Looks to be the start of a cactus buck. Something went wrong with his berries. A cactus buck will not drop antlers and will remain in velvet. Antlers will continue to grow.
Agree looks like a buck that lacks testosterone due to alterations in testosterone level usually as a result of testicular trauma, undescended testicles or from the effects of disease affecting the blood supply to the testicles.
I have only seen one deer that had an antler that looked like that. The other one did grow out about four to six inches but had no typical shape of size. The property owner said the same thing, a testosterone problem and they culled him out late season.
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