The problem is that the release may be wrongly credited on the sleeve/label, but the registration and copyright correctly held. It's often printer's errors or record company cock ups. It's not hijacked content, or copyright disputes - but original errors on the releases. The problem is that if I put down a false author for a work that my father wrote purely due to a misprint - then Google picks it out as fact. That information, if used as a source of who wrote a song, becomes a myth and helps to destroy the copyright and reputation of the songwriter.