I don't believe I would have ever said anything like that, at least not in reference to Black Korina. Maple, on the other hand, can be problematic due to its being a closed-cell wood and having spurious end grain exposures over its surface. You can end up with a splotchy finish that isn't very attractive. Although, even that can be forced to behave. A little sealer or a wash coat goes a long way toward evening out its response to stain.