As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOG PAGE 21133. DISCREPANCY: IN CRUISE FL 330 #1 ENGINE VIBRATION SPIKED TO 4.5 BOTH CHANNELS ON VIBRATION MONITOR WITH NOTICEABLE INCREASE IN AIRFRAME VIBRATION. AS PER EMERGENCY CHECKLIST ENGINE WAS SHUT DOWN AT 12:40Z ALL OTHER ENGINE INDICATIONS APPEARED NORMAL. AIRCRAFT RETURN TO KMIA AND LANDED WITHOUT INCIDENT. CORRECTIVE ACTION: