Could be a simple as S-roof glass and seal is dirty or misaligned when "closed."
Or roof drains are blocked.
A lot of dirt can keep roof open enough to leak.
Front hinge parts can wear and/or bend and roof doesn't closed right w/o you checking every time you open it.
Example: I have to pull the glass forward before closing to make sure close right or r-side can leak.
The hinge tabs bend if hit or have problems installing after glass is off. Glass puts all the weight on the tabs if you have problems taking glass off or in like loosing you grip or too short/weak to handle it w/ hands outstretch to pickup the center of glass. Even New tabs can have same problem if you remove the glass only 1 or a few times.
While both of these often leak on the seat(s) or floor directly, could flow to B-pillar or other weird places.
S-roof unit is design to allows some water in it and drain tubes flows...
Block drains or parked on on hill then drains won't flow right or not at all.
Could be rood studs have problems and roof itself and/or rear clip lets water in and Maybe affected by how you parked too.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)The Ogre's Fiero Cave[This message has been edited by theogre (edited 01-10-2022).]