As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
***WHILE A/C WAS OUT OF SERVICE FOR A HEAVY CHECK*** EXTERNAL FUSELAGE SKIN, UNRECORDED BLENDOUT FOUND AT SKIN FR3+12" & 2" BELOW STGR12R RVSM AREA. BLENDED AREA FOUND TO BE WITHIN LIMITS IAW ETD2020-170-001206. A/C REMAINS OUT OF SERVICE FOR HEAVY CHECK COMPLETION.