The Energon Pub

Specifically, it's First Strike Prime (I also have the standard, Robo-Vision and Battle-Damaged versions and none seem to have this problem).

Basically, when transforming to robot mode, the truck tail-lights act as a peg which then snaps into the sleeper section which becomes the robot knee.

However, my left knee doesn't snap together at all. Not sure if the connection's too loose or too tight. Anyone else heard of this problem, or know of a solution?

Thanks in advance!