E.g. using search for the type "Cleric" with the frame "Red" will yield Sculptor Medic and Ivory Priest in the results.

Maybe it is the OR searching, even though AND may be wanted instead; maybe it is an entirely different criteria. I don't know, though (I had not managed to get the search to work at all, but managed to search by downloading the XML.) (I would want to search by SQL, which can avoid this problem.)

I think, it's just something silly like the word "artifact" containing an 'r' and the colors using just their letter as identifier. :)