Hello, does the glass panel sit flush and appear to be fully closed? If so, that alone should be sufficient to preventing a water leak.
The sliding sunroof - and any roof opening - is not "weatherproof". It is expected that water will get through the cracks and into the channels around the roof opening. These channels are a barrier to prevent water from getting inside the vehicle through the roof opening.
The trick is - the water that enters this channel must be then funneled away from the roof properly to prevent it from eventually overflowing inside the roof opening. This is carried out via drain tubes that take the water to the side pillars and out of the vehicle.
Leaks inside the vehicle happen with either the drain tubes become clogged or dislodged, or debris builds up in the roof opening area.
Sure, the "seal" or weatherstrip around the glass should be inspected and serviced as needed, but they alone do not prevent water from getting inside the vehicle.
Use this link to find some shops near you that can help with your concern:
www.repairpal.com/repair-shops
