Chaos Vehicle Engine RPM while in air

When using Chaos Vehicles, why is it that when the vehicle is in the air the engine will not increase RPM until the vehicle has landed back on the ground?

The input is being received for throttle as I can have arcade controls while in the air, but the engine simulation seems to stop working while the vehicle is in the air.

What then do I need to change to make that so, and/or is this a bug/oversight with the component?