As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: SHORT TERM ACRID LIKE ODOR IN COCKPIT AND CABIN, DISSIPATED RAPIDLY. FLIGHT ATTENDANTS NOTICED SAME ODOR UPON GATE ARRIVAL. WHILE TROUBLESHOOTING, FOUND LAVATORY WASTE FLUID DRIPPING INTO LEFT HAND RECIRCULATION AIR FILTER AND LEFT HAND RECIRCULATION FAN. MAINTENANCE REPLACED RECIRCULATION FAN BECAUSE OF CONTAMINATION FROM LEAK, REPLACED PER MM 21-25-01 AND PERFORMED SATISFACTORY OPERATIONAL CHECK.