It's clearly a bot/AI doing the flagging. In another comment on this page I mentioned that I get copyright flags for Gregorian chant and polyphony which is not

It's clearly a bot/AI doing the flagging. In another comment on this page I mentioned that I get copyright flags for Gregorian chant and polyphony which is not only 700+ years old but has ALWAYS been in the public domain -- but I get these notices on the YouTube videos within about 90 seconds of completing a live-stream of the Sung Catholic Masses in which the music was performed. Nobody at YouTube is watching this in real-time and saying "Yeah, such-and-such Renaissance Revival Group cut a CD 12 years ago with this music: I suspect your of copyright shenanigans." This stuff is all automated and the default is to "You're a violator!" because not doing so would be to open YouTube up to the liability of knowing they might have copyrighted material on their platform and they did nothing about it.