This isn’t a bug.
AngularVelocity is what you need to set. Not AngularSpeed. All I did was use the Replace tool to change all 3 places you used AngularSpeed. It works just fine.
And I never use the default MotorMaxAcceleration and MotorMaxTorque settings. If the MotorMaxTorque is too high for a vehicle wheel it starts to jump and jitter around.
For most things I choose a much lower acceleration of 10 to 100, and then set the torque to whatever value gets my mechanism to work plus a little bit more.
Also, when setting up a HingeConstraint try to get both Attachment’s yellow and orange arrows facing the same direction. Yours are 90 degrees to each other so that’s why the red bar flips in the first second after you click Run.