I had a copyright claim on a clip of my band doing a cover of a song we hadn't written. Almost immediately a copyright notice come up. That was not a surprise but but the claim was not for the original of the song. It was a totally different song that happened to start with the same opening chord - E major.
There is a option to acknowledge the claim, or to assert copyright yourself but no way of saying the claimant is wrong. I tried to follow this up but the response was that if I am not the song owner, it's not my concern.