As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNIDENTIFIED ODER CONT. SMELLED LIKE BURNIG PLASTIC ACCOMPLISHED POST FLIGHT DEBRIEFING WITH INBOUND FLIGHT CREW FOR ODOR IN AFT CABIN. REF TASK 05-51-26-800-801 C1 AND FORM 46-6020. RAN ENGINES AND APU (HIGH POWER0 WITH ALL CABIN SYSTEMS ON INCLUDING COFFEE MAKERS AND WATER HEATERS, COULD NOT DUPLICATE SMELL.