I have alerted NVIDIA to this issue (it seems internal to PhysX).
Using AddTorque to apply a rotation to a skeletal mesh does not always provide the expected results if a fixed time step is being used. When doing this to the Owen character in the Content Examples project, the character no longer rotates if the fixed delta time is 0.02 or higher.
Opening the Owen Physics Asset and setting the Angular Damping for the Pelvis bone to default (0) restores the rotation effect. The Angular Damping values for all other Bone with Bodies in the physics asset does not appear to have a visible affect on the rotation.
Owen will begin to rise, but no longer rotates.
Owen continues to rotate while rising.
Head over to the existingAnswerHub thread and let us know what's up.