Looks to me like the maker was just pleating to a set dimension, and letting the tartan pattern fall where it may. Each pleat displays a little more of the tartan sett, as evidenced by the way the red stripe gets wider and then narrower again as the pleats move across the back. In past discussions, I think it's been called pleating to the random.

As I understand it, there's really nothing "wrong" or "bad" about this. In the days before tailored kilts (and perhaps even in the early days of tailored kilts), I would imagine that pleats were done this way as a matter of course. It may look odd or bad if one expects all kilts to follow a certain pleating concept, but it may very well be that the old tradition is still alive.

Do you know who made this kilt? Or at least whether it was made in Scotland?