Door Membranes Perished. (behind the door cards)
Common problem
Fix it with plastic bags like Rubble sacks stuck on with strong tape like duck tape or silicon sealant
If this isn't it, then there are a couple of other things: Sunroof drains blocked. (Unlikely as the seats not wet) Scuttle tray drains blocked (more likely) But try taking your door cards off first, and see if the membranes are hanging off!