Another possibility is that there's rust underneath the windshield seal. I found mine was still leaking after welding the sunroofs shut and following the TSB for the leak. I eventually had to have my windshield pulled to weld in new metal to fix the leak. If you pull the headliner you can see the rust up at the top of the glass in the corners. I posted some pics of my repair in the imgur link below.

https://imgur.com/a/ieYuMb2