I record on my kneeboard the engine and airframe times before engine start and after shutdown. Times and fuel added are also recorded for every refuel.

Today, when I entered fuel data in my spreadsheet, I noticed that airframe and engine hours were lower than recorded at the previous refuel. I reviewed my G3X data logs and my kneeboard records and found that the error happened when the airplane was grounded for installation of my hall effect current sensors.

Airframe time was reduced by 7.1 hours and engine time was reduced by 6.1 hours. Several G3X configuration changes were made during sensor calibration but none of these changes should have changed engine and airframe hours.

I suspect a firmware defect and will give my data to Garmin.

Has anyone else ever seen an error in G3X engine and airframe time records?