Fountain Fill thumbnails

I sometimes see the thumbnails for Fountain Fills as grayscale images which, obviously, makes it pretty impossible to select one as they all look basically the same. Of course, it doesn't happen all the time, but when it does, it happens whether I'm choosing them from the Object Properties dialog, or from Edit Fill. is this happening to anyone else?

P.S> This is my first post in over a week, and a message pops up telling me my posting frequency has exceeded my allotted amount. Really?