As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROPELLER IS UNCONTROLLABLE, TO LOWER PITCH, AT HIGH ALTITUDE (COLD TEMPERATURE). NEW PROPELLER FROM MANUFACTURER. INSTALLED SERVICEABLE PROPELLER. ALL SYSTEMS WORK NORMALLY. INSTALLED ANOTHER NEW PROPELLER, ALL SYSTEMS WORK NORMALLY. POSSIBLE WRONG GREASE IN HUB OR TOLERANCE TOO TIGHT. (X)