As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ALL 3 NO. 2 UPPER DU WARNING MSGS FLASHED SIMULTANEOUSLY BTWEEN 60-80KTS.NO M/C LIGHT. PER CREW, LIGHTS WERE ON AFTER ENGINE SHUT DOWN THEY STAYED ON FOR 2-4 MINUTES THEN WENT OUT. THE LIGHTS CAME BACK ON INTERMITTENTLY AND WERE FLICKERING. FURTHER DETAILS AWAITED.