GameGear games on SMSAdvance

When I launch any GameGear games (.gg files) with only SMSAdvance installed, it launches the game with inverted colours and broken audio, and I cannot press "start". I tried R and all other buttons. It's as if the emulator is trying to run the game on Master System?

All the Master System games (.sms files) work perfectly fine.

Any idea how this could have happened?