If you use the ram to prime, the spent primer may have been on the ram when you raised it and got shove into the pocket. Or it may have been in your tumbling media and got into the pocket during tumbling(?). But most likely it got mixed into your live primers somehow and was cycled through the system with the rest
(because it was spent it didn't right itself like the live primers due to it's weight).
BTW - That sharp-eyed girl of yours is cute as a bug's ear!
