As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROPELLER VIBRATION FELT IN BETA, 950, AND 1050 RPM. INSPECTED AND FOUND LEFT AND RIGHT REAR ENGINE MOUNTS STRUTS BROKEN. REMOVED AND REPLACED ALL ENGINE MOUNTS AND PERFORMED PROPELLER BALANCE. AIRCRAFT RETURNED TO SERVICE. REFERENCE PCAA9600275.