As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INCOMING VISUAL INSPECTION OF AN ANTI-ICE VALVE, SHOPFLOOR NOTIFIED THE ABNORMAL USE OF WASHERS BETWEEN RIVETS AND BUTTERFLY VALVE'S BODY. THESE WASHERS ARE MUST NOT BE MOUNTED ON THE PART ACCORDING TO CMM INSTRUCTIONS (CMM 30-21-52).