Anyone else have this happen?

[L. Cooper]

I think the reaction means a hit. But you can not predict what sort of hit.

I have seen several heart shot deer jump straight up in the air like they were on springs, and I have seen at least one that was just singed by the bullet in the brisket do the same dance (it was shot again seconds later when it stopped to try to figure out what was happening). I've also seen heart shot deer just stand as if missed. You can learn more from the blood trail than the deer's reaction to the shot, but blood trails can be hard to find.

Sounds like a bad shot. It happens. We must all admit it does happen, and do everything we can to make it happen as little as possible.