Strange Axle twist, how much would you allow?

It has a spool, and I have not seen it do a 'one wheel peel' yet....although there is a pic of it with 3 wheels in the air and the bumper and 1 wheel planted.....the same day he blew out the drum in the ******......hmmm think that may have something to do with it??????hehehehe

 

I pulled the axle after this past weekend and it did not change. Now I have already ordered a 35 spline set and spool from Mark Williams. So I just have to wait until they come it. Here is some video from last weekend.