[simmonsguns]

If the carrier is sticking up than the next shell will just drop out of the gun and not onto the carrier.
I have seen this before, check the carrier spring for function, just push up on the carrier there should be enough tension that the spring will push it back down, it could also be binding inside the receiver also.

 

[simmonsguns]

If all else fails, call Midwest gun works. ken and mike have helped me with some of the newer gun models that we don't see much of.
Shell latches wear out but in a gun that does not have much use on it or at least under 1,000 rounds, something is keeping the latch from returning back to full capture.
I checked the shop for one today and no luck, let me know what you find out.