Rick,
The iFly datetime comes from the GPS feed. So if the navigation app starts before a GPS signal is established (not a full lock, just need one satellite in view) - the datetime will be incorrect with the log file is opened. So if you are booting up in a hangar or something, you may want to defer starting the nav app until the unit is on for a minute or so - to make sure the date is set first.
Thanks,
Walter