As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR RETURN FOR YELLOW HEADING FLAGS. PUSHED BOTH CA/FO HEADING SLAVE DID NOT FIX FOLLOWED QRH TO COMPLETION DID NOT FIX AVIONCS HEADING FLAG INTERMITTENTLY ON IN FLIGHT BOTH SIDES APPEAR 3 DEGREES OFF FROM STANDBY HEADING INDICATOR. MAINTENANCE REMOVED AND REPLACED NR 2 AHRS P/N 622-6190-113, S/N OFF 2179, S/N ON 3033. ALL CHECKS GOOD IAW SF340 CHAP 34.