Given they are using an array of freely floating magnets it doesn't seem like a big "breaking". It's possible to create normal mechanical systems that also "breaks" Amontons' first law. For example, imagine a surface with an array of spring loaded pegs poking out of holes on a teflon surface. At light loads the object will have to slide against the pegs. But push a little harder and the pegs will push down into the holes of the surface and the object is now sliding on teflon.