Because this kind of thing almost certainly crops up in the "related work" section, which is a weird section of the paper that doesn't really involve any of the actual core research. It's essentially a tiny little bibliography intended for people who don't know the literature, so it doesn't get the same level of deep care as the original work. I suspect often people copy titles and fragments from their previous papers or from other papers, on the theory that they can only make the section less accurate by adding novelty.