As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 4175, THE CREW REPORTED THAT WITH DEICING SYSTEM ON THERE WAS A STRONG ODOR LIKE BURNING PAPER IN THE COCKPIT AND CABIN THAT SUBSIDED DURING FLIGHT. THE AIRCRAFT LANDED AT IAH WITHOUT INCIDENT WHERE MAINTENANCE PERFORMED OPERATIONAL TESTS OF THE ANTI-ICING SYSTEM WITH NO DEFECTS NOTED. THE AIRCRAFT WAS THEN APPROVED FOR RETURN TO SERVICE.