I have seen that happen several times using archery equipment. Never had it happen while gun hunting, seen it on the outdoor shows plenty though. Must be sorta common.

it s very common for a turkey to jump up on the shot turkey....i had 6 big jakes trying to jump on there downed companion....charlie

I've killed two gobblers after they pounced on a bird I'd shot. Both were accidents as I thought the second bird was the first one getting up to run off. On two other occasions I got two Toms with one shot, again, by mistake. I guess there's bad luck in turkey hunting...and then there's my luck (a.k.a. dumb luck).