Sounds like a very high hit that shocked the spinal cord, that is the only real shot that can “drop” a bull that then gets right up. Without a limp.
I can’t believe that a 7 rem mag bullet didn’t penetrate at 200.
There is no explanation that makes any sense to me somehow all that lead and copper just stopped without penetrating. I have captured multiple chunks of copper on the far side of an elk with highly “explosive” bullets.
The far more likely explanation is a shot that went high and shocked the CNS.