As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 3518, THE CREW REPORTED THAT THE LEFT MAIN LANDING GEAR WOULD NOT RETRACT UNLESS CYCLED TWICE. THE AIRCRAFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE SERVICED THE MAIN LANDING GEAR ACCUMULATOR, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.