[Plugin: Better WordPress Minify] box-sizing being disrupted

I have this in the top of style.css:

* {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

I also have about 25 different css files being enqueued by plugins etc.

When I run the minifyer, everything works except my box sizing settings. That impresses me, because I expected more conflicts than that.

Any idea what would be making that one setting break?

http://wordpress.org/extend/plugins/bwp-minify/