Every time you upload something to Youtube that includes any kind of music, you get a copyright claim. Doesn’t matter if it’s royalty free music you paid for or something you made yourself. The claim is always linked to the music of the copyright holder and it’s always something completely different from what you have uploaded, of course. It’s some kind of annoying, automatic thing Youtube is doing every time.
If you’re a Youtube partner and plan to make money from advertising, then it might be a good idea to wait for a month before sharing your video. That’s about how long it’ll take for Google to accept your complaint and let you start monetizing your clip.
This is how absurd it can get. “…cat had copied part of a song called Focus belonging to EMI“.