Has it always had issues with bubbles in the claws? Or is a recent event?
If it's a recent event: Check the alignment of the mold you are having issues with. I'm betting it got banged (or even worse dropped) and it's slightly askew....blocking off that vent somehow as it gets to the very end of the fill and there is less pressure to push the air out.
If it has always had an issue check and see if there is a burr in the tiny vent off the tip of the claw.
Otherwise, I'd call Do-it Customer Service and ask them for a replacement.