Probably due to not being hemmed and the extra pleats. Maybe as much action as can be expected of a reverse Kinguise pleat system. Of all my Utilikilts, the denims get the best pleat action and lay - probably due to the diagonal flexability of denim.
I think of denim as pretty stiff compared to cotton drill fabrique, so it is less prone to wrinkle. Who is this guy called Kinguise?