As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED SMOKE TOILET CAUTION MESSAGE ON DESCENT AFTER SWITCH TO APU BLEED. NO SMOKE IN CABIN, BUT FAIRLY STRONG SMELL WHEN BLEEDS WERE SWITCHED. MESSAGE WENT AWAY ON ITS OWN AFTER ONE MINUTE. CREW LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND FOUND FUEL LEAKING FROM APU FUEL CONTROL THROUGH OVERBOARD DRAIN. MAINTENANCE REMOVED AND REPLACED APU ASSEMBLY AND PERFORMED CHECKS USING AIRCRAFT MAINTENANCE MANUALS. AIRCRAFT RELEASED FOR SERVICE.