I found this issue by accident.
The example .MFA is based on firefly example : Basics - Splitscreen.
Add a new event :
Sometimes people use this action to start a new game.
* timer > 2000
storyboard controls : Restart the application
Build the application (sorry but the .exe exceeds the limitation of .zip file size) and run it, then look into task manager :
First run : about 20MB
After restart several times : more than 110MB
I have tried the same thing in a traditional 2D game without firefly , but did't notice any leak.
So is this a bug, or there is something wrong with my settings?