braketorque making rigidbody sleep

Whenever i set my wheelcollider’s braketorque to something other than zero it makes my rigidbody sleeps after a while.

My object is not moving, just standind still in a terrain. After like 3s the rigidbody attatched becomes asleep ( wheelcollider.attachedRigidbody.IsSleeping() is equal true), so if i move the terrain the object doesnt fall or goes up with it.

Is that behaviour the correct one?

Add a simple scene with a simple car.

Create a script with

void Start()
{
foreach(WheelCollider c in m_wheelColliders)
c.braketorque = 5f;
}

void Update()
{
print(m_wheelCollider[0].attachedRigidbody.IsSleeping());
}

Let it fall over the terrain, and watch the print goes from false to true. Then move the terrain downwards and check out your rigidbody standing still!