As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT 0635, RTB IN MSY DUE TO AN OILY SMELL IN THE CABIN WITH THE MID AND AFT LAVATORY SMOKE DETECTORS SOUNDING. PACKS WERE OPERATING FROM APU ONLY. REMOVED AND REPLACED RIGHT ACM PER AMM 21-51. OPS CHECK GOOD. COMPLIED WITH NO-GO ODI PREVENTION PROGRAM 2172.