it's called bias and, to my knowledge, every woven fabric so far has it. what it means is under stress the fabric will stretch or deform more in one direction than it will if the same force is applied in the other direction.
this applies to the construction of kites where the maker wishes to eliminate or reduce stretching of the fabric in a certain direction.
on more finely made kites the orientation of the fabric bias is most definitely intentional.
generally speaking on more well made kites you'll find the ripstop pattern of the fabric aligned with the direction of stress. if you were to look along the spine of the kite the boxes will be aligned with it, and along the leading edge they'll also be aligned, but where these two pieces of fabric meet you will have the boxes at an angle to each other.
you can see exactly this principle, in the picture below.thanks to skippy for posting this picture elsewhere on the forums.