As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BLUE/GREY SMOKE IN COCKPIT AT 35,000 FEET. SMOKE DISSIPATED PRIOR TO RUNNING SMOKE REMOVAL CHECKLIST. APU WAS DEACTIVATED PER MEL. ANOTHER STATION LATER PERFORMED PACK BURN OUT AND FOUND NO SMOKE OR OIL SMELL IN CABIN. THE APU WAS REACTIVATED.