Wagon - Leaking at the roof rack

I had a water leak in the roof of my CTS wagon which appeared at the right rear of the headliner (above C & D pillars). After looking online it appeared to be most likely coming from a clogged rear sunroof drain. I tried to clear it with trimmer line, but it didn't solve the problem. I didn't see any signs of leaking in the sunroof seal either (which would have been expensive to replace). So I dropped the headliner on the right side to see if I could locate the source. No water showed when I poured a waterbottle over the sunroof, or even when i poured in the sunroof tracks. However, i did notice water coming in when the water came across to the roof rails (for the roof rack). I don't have a roof rack, so the metal side rails are just covered with the t shaped rubber molding. There was no obvious damage to this molding, but i pulled it up and tried pouring water in the track. This also did not show a leak. It appears that water coming off the roof was going down between the body and the metal rail and was not draining, but escaping through a broken pinch weld of some sort

I tried a temporary solution by running a bead of caulk along this line. It doesn't show at all when covered, and I have no more leaks.

Has anyone else experienced this? Is there a more permanent repair? Do I need to replace my molding?

dropping the headliner was not as bad as I expected, but I did have a few tips.
Having a trim panel remover was key. Also, there are two clips at the rear of the headliner for which the mounting point is just hot glued to the headliner. Be very careful to pull straight down only so as not to break off a mounting point.

And folex works wonders to remove water stains.