As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INVESTIGATION FOR MELTED AND COLLAPSED EVA OUTFLOW VALVE TUBING FOUND CABIN AFT VENT WAS BLOCKED WITH BAGGAGE AND AIR VENT WAS DETACHED. APPARENTLY CABIN AIR (HEAT) WAS SUFFICIENT ENOUGH TO MELT/COLLAPSE TUBING. THE ONLY DAMAGED TUBING WAS AT THE AREA OF THE AFT VENT.