As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BURNING ODOR COMING FROM BLEEDS AT POWER SETTINGS BELOW 25 PERCENT TQ. ODOR GRADUALLY DISAPPATES AT HIGHER POWER SETTINGS. INTEROGATED CDS FOR FAULTS , NONE NOTED. GROUND RAN BOTH ENGINES, NO ODORS NOTED WITH BLEEDS SELECTED. PERFORMED PURGE OF AC DUCTS IAW DH8-400-SL-21-012A. PERFORMED ENGIINE OIL CHECK, LEVELS OK. COULD NOT DUPLICATE. RETURNED TO SERVICE. NO PARTS REPLACED.