*g* Yeah, it was a bug for a while, a while back: when people removed interests, the number was getting decreased by 2, not by one (the count was decremented twice by accident), so if only one person had the interest listed, it flipped out and recycled back around.

We fixed the bug, but didn't fix the interests counts on dreamwidth.org itself. Need to get around to it one of these days! I think you might be able to fix it by adding the interest yourself, then removing it, but I'm not sure; I should experiment with that a bit.