Headliner/sunroof leak

Attached is a photo showing where I have outlined the stain with baking soda. It's a w219 CLS, same parts as w211. Does anyone know if this is a seal or clogged drain issue, in case the pattern is familiar or obvious? From what I understand in general, sunroof seals are often more for wind buffering and water is planned to flow into the drainage paths (even if the panel seal is pulled back from the corners), but I wouldn't discount it for sure, I just don't know.

Attached is a photo showing where I have outlined the stain with baking soda. It's a w219 CLS, same parts as w211. Does anyone know if this is a seal or clogged drain issue, in case the pattern is familiar or obvious? From what I understand in general, sunroof seals are often more for wind buffering and water is planned to flow into the drainage paths (even if the panel seal is pulled back from the corners), but I wouldn't discount it for sure, I just don't know.

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