As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DIRTY SMELL/HAZE IN CABIN AFTER TAKEOFF, LAV SMOKE DETECTORS WERE GOING OFF. REMOVED APU SURGE VALVE DUCT, NO SIGNS OF OIL RESIDUE. REINSTALLED DUCT AND LEAK CHECKS GOOD. PERFORMED DUCT BURN PROCEDURES PER M/M, NO SMELL NOTED MCO AND PLAC REMOVED.