Why can't I substitute Minion font for another in a document?

When I highlighted a QuarkXpress document and tried to substitute its font with my Minion Regular, I got a lot of mush along with some Minion Regular,

BUT when I touched my cursor to the mush as well as non-mush, it ALL showed Minion to be the type in my Quark font window.

When I substitute other PostScript fonts, they work okay.

Minion also works in my Microsoft Word docs.

     P.S. I also have Minion Expert installed in my system.

          Thanks!