As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE REPLACING A WING DEICE BOOT, DISCOVERED THAT ONE OF THE HEATED LEADING EDGE RETAINING SCREWS HAD MADE CONTACT WITH THE WING SKIN AT WS60. THE DAMAGE IS BEYOND NORMAL LIMITS OF 10% OF SKIN THICKNESS. INVESTIGATION REVEALED PROPER PN AND LENGTH OF SCREWS WERE INSTALLED, AND THIS SCREW DOES INDEED CONTACT LEADING EDGE SKIN WHEN INSTALLED. FOUND SIMILAR DAMAGE TO OTHER WING.