It's more then likely the extractor spring that's located internally. They should have sent you a replacement. If not your going to have to get one from them. They don't last as long as they claim to.
I'm a big fan of the XL, I have one on each of my 3 open pistols. Other then the up and down buttons sticking they have been great, for me. SRO is also a great choice!
This is the best deal you will see from them.
If anyone is on the fence about this set up I would jump all over it. It is a great cart and bag Combo, much better then DAA.