As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STRONG BURNING SMELL IN CABIN NEAR OVERWING EXITS WHEN MAIN SUPPLY TEMP EXCEEDS 80 DEGREES F. ISOLATED PACKS WITH APU AND ALL ENG BLEED SOURCES. RAN SUPPLY TEMP TO 130 DEGREES F WITH EVERY COMBINATION POSSIBLE. NO SMELLS OF ANY KIND. REPLACED BOTH WATER SEPARATOR BAGS AS PRECAUTIONARY.