I wouldn't allow it. The feat is kitted up to assume that it's your character doing the jumping, not the mount. Plus, it would be pretty insane if used in conjunction with spirited charge.
I know this is likely a silly question, but couldn't the Mount charge, and the PC then leaps OFF the mount and perform a charging Leap Attack?
Or does something make that impossible by RAW?
Disclaimer: I know little to NOTHING about mounted combat, but thinking about the image, it seems plausible.
I would think so, but it would then negate the benefits of being mounted in future rounds, and any benefits you'd get from charging with a lance.
but, it's a cool image of charging and leaping off the back of your mount to get into the thick of melee. Might be more barbarian-like than paladinesque, though.