This observation doesn't apply to the model above, but my model crashes consistently if there are any controlled joints with associated groups set to ignore or static. To stop some objects from falling from my model I had set their overall groups to 'static/ignore'. When later connected to a joint I had overlooked some groups in the static/ignore states, bug splats occurred until I corrected the states. The bug splat sometimes occurs at the point the play button is pressed, but also when the reset button is pressed after successfully playing the animation.