If in a hierarchy, a Rigidbody is parented to an ArticulationBody, and connected to it with a joint, then its position won't be correctly reflected by the Transform, even though the actual position as seen by the physics engine was correct (see the Physics Debugger).

To reproduce:

1) Open the project attached to this case
2) Open the art-test scene
3) Press play
4) Make sure the physics debugger is open (Window - Analysis - Physics Debugger)
5) Notice that the sphere on the right ("parented") is not drawn solid. This is because the visual position (Transform) is different from the physical position (as shown by the Debugger)
6) Notice that the magnitude of the drift depends on the "Target Velocity" of the child articulation.

Expected: The sphere on right should look like the sphere on the left, that is the physical position should be identical to its transform.

WORKAROUND: Unparent all Rigidbodies from ArticulationBodies.