Constrained HingeJoint bug in Unity5b16 [FIXED in b17]

I'm running into trouble with a hingeJoint! It works great if the rigidbody of the connected item is unconstrained, but as soon as I put constraints on it (any combination of x / y / z, position or rotation) it starts jittering and glitching. Is anyone else seeing this or is it the way I've coded it up?

 

Curious further thoughts; here's a step by step:

- Instantiate two gameobjects in the world, each with a box collider, and constrained Z motion and X/Y rotation.
- Programatically configure a hinge joint and connected the two boxes.
- Movement of one box will result in jitters and glitchiness; both boxes will launch off into space.

If I pause the editor right after making the hinge, and manually de-select the constraints on the grabbed object, it seems to move fine, however, if I programatically set the RigidbodyConstraints to .None during the creation of the hinge joint the original behaviour persists.

I think the physics engine isn't properly updating the state when using programatic designs?

(Same setup works great in 4.6.1)

 

Fixed in Beta17. Thanks!