Have a relatively new (few hundred rounds) G36. The problem is that, when it's fired and the trigger held back, the slide fails to return completely into battery. When I release the trigger to the reset point, the slide moves forward into battery. GLOCK looked at it, switched the recoil spring assembly, and sent it back to me. The RSA was virtually new, so maybe the old one had an issue, but the same problem happens with the new RSA, so I don't think that was the issue. What is there that could cause the slide to hang back like that? I am trying to imagine what moves or changes inside when the trigger is held back, as opposed to releasing it forward, to see what (if anything) I can do about it. Any suggestions?