I believe I have seen it once, a long time ago. It was after I'd replaced one figure with another, by double clicking on the library instead of using the double check marks. It was deliberate, I can't remember why I wanted to do that, or why I looked inside the CR2 afterwards. Ever since I saw that, I've always replaced figures by deleting the first one and loading a fresh one to take its place. The CR2 reference seemed like an unreliable thing to have in there, since a CR2 is liable to be moved or deleted in the future without much thought being given to it. Of course, I don't always look inside a CR2 that I've saved, so it might be happening a lot more often for all I know. But statistically, I doubt it. :)