As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OPERATOR NOTICE LOSS IN ENGINE POWER. KEYSTONE TESTED THE ENGINE TO VERIFY POWER NUMBERS. TECHNICIAN INSPECTED THE COMPRESSOR TO DISCOVER DIFFUSER VANE ASSEMBLY HAD VANES SEPARATING FROM AFT PLATE. PART PREVIOUSLY OVERHAULED FROM APPROVED VENDOR.