Mine does the same. Load EFB flight plan and no start flight.
I had not noticed because:
The EFB does not have a method to create or save the Flight Conditions or Time.
So, I always:
Select the Departing airport to match the saved EFB IFR flight
Set the Flight Conditions (month, day, and time)
Then
Display the EFB
Then Load the IFR saved flight.
Send it to the ATC
Send it to the Avionics
Close the EFB
Start Flight