As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE ENGINE COMPRESSOR STALL: UPON REACHING FL410 AND BEGINNING TO REDUCE THRUST FOR CRUISE, WE EXPERIENCED THREE DISTINCT COMPRESSOR STALLS WITH AIRCRAFT YAW AND A NOTICEABLE DROP IN N1 INDICATION ON THE NUMBER ONE ENGINE. CORRECTIVE ACTION; SWAPPED EECS & REPLACED SUSPECT FAILED LEFT ENGINE INTERCOMPRESSOR SERVO VALVE. WORK DONE IAW PW EMM 75-30-01. OPS/LEAK CHECK GOOD