[2018 S60] : Water leak, likely sunroof

[s2zeller]

We had some moderately intense rain a few days ago, and I noticed this morning that some had gotten into the car. An umbrella on the passenger seat was hiding a wet area and the rear passenger-side floor mat had the remains of some puddles (and was damp on the other side). There wasn't any moisture issue associated with center console or on the driver side.

I immediately suspected sunroof, especially after noticing that the plastic edging around the cutout had popped off at the back seam. I also noticed that the sliding hatch was pushed too far forward, leaving a gap at the back (which I suppose I could have done by sliding it forward with a little too much force).

I tested the sunroof control and it seemed to be sealing the window properly in place (i.e., the sunroof hadn't been explicitly open).

As I've owned Volvos for 25 years and never had a sunroof issue, I'd like to know what I should be looking for when I take a look at it this weekend.