Quark 6.0 printing

I have recently installed Quark 6.0 (mac, OS 10.2.6), and noticed that when printing text in Pantone (solid, uncoated) color the text looks like it has a gradient (light to dark). Does not seem to have rhyme or reason (eg, mid-word to end of paragraph). Prints fine in Quark 5.

Anybody else have this problem and/or know what to do about it?

Thanks.