Ok then the ones you are using are not matching up right ! , pull the center post out on one of them farther and see if that works please
You can also pull on the center post on the infinity a bit just be careful and do not pull it out to far.
What carts are these ?? this sounds like there may be a bad batch or ????
use a small screwdriver or knife and wiggle it around a bit and it will come up a little.
I'll remember that if it happens again. I've got myself on the notify list for the fusions I keep hearing so much about.