As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4172 THE CREW REPORTED THE COCKPIT HAS STRONG ODOR COMING FROM THE GASPER. THE SMELL MAY BE FROM LAVATORY FLUID. THE AIRCRAFT WAS REMOVED FROM SERVICE. SERVICED THE LAV, THE SMELL DISSIPATED FROM THE COCKPIT, NO DEFECTS NOTED AT THIS TIME. THE AIRCRAFT WAS RETURNED TO SERVICE.