Thank you SuperScamp for agreeing with my post.
I have seen several break from this happening,including my own.
It will keep happening too unless you limit the twisting of the rear end.(either install a snubber or some sort of traction bars.)
I have Calvert mono-leafs and Caltrac bars on my Demon.
I seen some beat up driveshafts that didn't hurt anything.
Good luck.