As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK, DURING FLAP RETRACTION, THE L/E AMBER LIGHT AND NR 4 KRUEGER FLAP GREEN LIGHT SHOWED FULL EXTEND. RECYCLED FLAPS, NO HELP. VISUAL INSPECTION SHOWED NR 4 KRUEGER FLAP WAS STUCK FULL DOWN. REMOVED AND REPLACED NR 4 KRUEGER FLAP ACTUATOR PER MM.