As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING SCHEDULED INSPECTION, REMOVED HEAT BLANKET ASSY FROM THE APU EXHAUST PIPE. NOTICED SMALL PIECES OF WHITE HEAT BLANKET MISSING AND WAS WATER STAINED. THERE IS A REPAIR FOR THE BLANKET BUT WE FOUND THE COMPOSITE INNER SKIN TO BE SOFT IN A 5 TO 6" AREA.