As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 3133, THE CREW REPORTED A BURNING SMELL INTERMITTENTLY EN ROUTE, AND ON APPROACH. THE AIRCRAFT LANDED AT IAH WITHOUT INCIDENT WHERE MAINTENANCE INSPECTED THE AIRCRAFT CABIN AND COCKPIT FOR A BURNING SMELL WITH NO DEFECTS NOTED. THE AIRCRAFT WAS SUBSEQUENTLY APPROVED FOR RETURN TO SERVICE.