As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) APPROXIMATELY ONE HOUR AFTER DEPARTING THE CREW OBSERVED A FINE SPRAY COMING FROM NR 2 OUTBOARD NACELLE DRAIN. THE AIRCRAFT RETURNED TO YFB. TROUBLE SHOOTING DETERMINED THAT THE FCU SEAL HAD FAILED. THE UNIT WAS REPLACED , THE AIRCRAFT GROUND RUN RETURNED TO SERVICE.