Anthony Folk

Hi, I have a 2007 Sierra 2500HD Classic Crew Cab with the sunroof. When it rains, the bottom, rear of the sunroof leaks. It is dripping onto the headliner through those 3 tabs (mainly the center tab) which I believe holds up the sunroof trough drainage frame. The 3 tabs are right next to the drainage hose which is attached and working. The drain tubes are working as well. Any thoughts where this water is coming from and potentially how to fix?