Ok maybe I have had it wrong all these years but here goes..you have to have some angle on a u-joint or the needles in the caps do not rotate, If they dont they soon get flat spots and poof dust.. If that joint is close to 0 angle..the pinon side of the joint could be zero..I would throw a set of shims under it and see if a degree or two doesnt help..
The only thing I know for sure about drivelines and thier mystical angles etc..Is just about the time I think I understand it, everything I thought I knew turns out to be wrong and I should have done some absurd ass backwards thing that I was sure was wrong..
That yoke being tweaked would be a tough deal..with out pulling it and putting it on a known flat surface it would be tough to tell.