Several of mine have been known to do this. It's normal. In the wild, Ball Pythons will eat carrion that they stumble across. So they do have the capability to distinguish live prey from dead prey. If they realize it's dead food, they don't need to constrict it to kill it and will simply eat. My boy Asher did that his first feed, and all of us were so puzzled (he was my first snake and I didn't know it was normal). He literally just slithered up to where I was dangling his food, touched it with his nose, then slowly (and very lazily, I might add) opened his mouth and began to eat. We were too surprised to even video it, though we should have because it was one of the most entertaining feeds we've had as far as lazy snakes go.