I keep an eye on my snakes once they've taken prey, & sometimes I "help" a little using my tongs to adjust. My 19 year-old corn snake has a good appetite
but often has trouble eating: he'll grab it, then go for the wrong places like yours did, only then he drops it & wanders around...if I don't intervene, he'll end
up not eating, but typically after a couple tries (w/ my help) he gets the right end. He never had this trouble when he was younger...grandpa needs reading
glasses now.His vision isn't what it used to be & it makes a difference. I've seen this in other old rat snakes too.
It's common to see young snakes of all kinds trying to eat sideways or butt-first. Their excitement appears to take precedence over using visual clues.