Sounds like a scale issue. I imported a skeleton from blender and it was 100 times too small, so I had to fix the scale in unreal by 100; whether it be sockets or importing animations.
If you select the constraint in the physics asset I saw -0.440393 in position 2, Y axis. This would have been correct if scale was right. There I had to change the value to -44.0393. If you simulate from here it throws everything into a spasm. There change the constraint rotation and move the pivot back to the original location.
The constraint will keep its rotation but the pivot will not cause any spasms in the simulation.