As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT NR 3522 RT ZONE HIGH TEMP LIGHT ILLUMINATED DURING FLIGHT. WING AND TAIL ANTI-ICE WAS ON. AIR RETURN TO MSP. MAINTENANCE FOUND WORN OUT NR 4 PYLON AFT OF HEAT EXCHANGER PERISEALS. REPLACED SEALS. LEAK CHECK GOOD REFER AMM 36-11-00.