So I've downloaded all kinds of fonts from here, and am mass-importing them into Font Book for Mac. So I create a new collection in the left pane, import the fonts I want into that (I've tried drag-n-drop as well as Cmd+O), and all imports well. However, I create a new collection, import those fonts into their collection, and yet those new fonts show up in the first collection, too!

For example, collection 1 has 50 fonts. When I add 50 fonts into collection 2, collection 1 suddenly has 100 fonts. Funny thing is, it isn't consistent. Sometimes it'll add the fonts to the wrong collection as well, sometimes it doesn't. Thoughts?! UGH!