The arc titan class ability, thruster, doesn't change key binding when swapping control scheme. Default control scheme and others use b (Xbox) for using the class ability, I use puppeteer which puts it onto a press of the thumbstick. The in game prompt in the subclass when equipping thruster says to double press the stick like it should, but this doesn't actually trigger anything other than crouching. To use the ability I have to press b twice like in the default control scheme.