As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE BEGAN TO SURGE WHEN PWR BROUGHT BACK FROM T/O TO MCT PWR SETTING. CONTINUED TO SURGE WITH POWER DROPPING TO APPROX 58 PERCENT. AUTO-IGNITION WOULD COME ON AND ENGINE WOULD RESTART. RETURNED TO DEPARTURE POINT. MAINTENANCE FOUND BOTH MONOPOLES TO BE SHIMMED TO THE HIGH LIMITS. SWAPPED N2 MONOPOLES AND PERFORMED GROUND RUNS. CND PROBLEM. PERFORMED MAINTENANCE CHECK FLIGHT WITH NO DEFECTS NOTED.