Nintendo's being a fucking piece of shit now, I uploaded a MKWii video and it says its a motherfucking MK7 recording. They don't even know where their own god damn music comes from.
It's usually not Nintendo doing the matching. YouTube has algorithms (That tend to fail) to detect copyright content. I had it happen like, 6 times on one video. I just disputed (And won) all of them, as none of them actually matched the content that they claimed it was.