Prevent motors from turning off in FW

My aircraft has a Y3 motor config. While in Manual mode (for testing), when I switch from MC -> FW, all the motors turn off. If I move the throttle, the front motors start to spin again, basically reacts to the throttle. When I switch back to MC, all the motors automatically turn back on.
How can I prevent the motors from turning off when in FW mode?

Could you raise an issue on github?