I have a gen 4 G19. I currently have a Grey Ghost milled slide with a Trijicon RMR and a Zev slide with a Holosun. When firing both milled slides and holding the trigger back after firing, the slide does not go completely back into battery. Only after I release the trigger does the slide goes back into battery. Obviously the OEM slide works flawlessly. I just don't understand. All Glock OEM for the frame as well as the Zev slide. The Grey Ghost slide has it's respective internal parts. I'm at a loss.What's the issue?