As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DISCREPANCY: REFERENCE LOG PAGE LP1170515-1. AIR-TURN-BACK ISIS ATTITUDE INDICATOR RED FLAG IN FLIGHT. AIRCRAFT WAS GROUNDED DUE TO DISCREPANCY. CORRECTIVE ACTION: MX REMOVED AND REPLACED ISIS INDICATOR IAW AMM 34-22-25 PB 401. OPS CHECK GOOD./END/