As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE SURGE ON TAKEOFF. ENGINE SELF RECOVERED AND CONTINUED NORMAL OPERATION. ENGINE EXPERIENCED GROUP 3 SURGE ON TAKE OFF. CAUSE OF THE SURGE IS OPEN CLEARANCES IN THE REAR OF THE HPC. FINAL FIX FOR SURGE ISSUES IS THE OVERHAUL OF THE ENGINE TO A RING CASE CONFIGURATION.