I don't see this happening in the demo scene - do you have Nolan's "Align To Ground" ability enabled?
Sorry, even with that enabled, I can't reproduce this in the demo scene... I've tried using both first and third person views. Have you changed anything else about the character/car/camera?>
I also just tried to reproduce it but wasn't able to. Are you running the latest version?
Line 367 of Drive will position the character according to the gravity direction. Unless one of the align abilities have been started the gravity direction should not change from Vector3.down.
m_CharacterLocomotion.AllowRootMotionRotation = true;
m_CharacterLocomotion.SetPositionAndRotation(startLocation.transform.position, Quaternion.LookRotation(forward, -m_CharacterLocomotion.GravityDirection), true, false);
It does look like my development version has different line numbers. Line 375 is correct for you though - is the gravity direction pointing in the Vector3.down direction?