As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IS CRUISE FLIGHT NG WENT HIGH AND BLINKED RED FOLLOWED BY CAS EXCEEDANCE MESSAGE. INSPECTED AND NO FAULTS FOUND. BELIEVED TO BE GLITCH IN GARMIN CAUSING FALSE INDICATIONS BASED ON THE GARMIN RECORDS FROM THE DATA LOGGER CARD. NO OTHER VISUAL OR AUDITABLE INDICATIONS OF NG OVERSPEED BESIDES GAGE FLICKER AND CAS MESSAGE.