When viewing composer by classical only, I get composers listed who are definelty not classical. For instance Roger Miller, the country artist/songwriter, shows up in classical composers. I don’t have Roger Miller listed in any of my file metadata, so it’s comping from Roon.
I also have Holland, as in Motown’s Holland–Dozier–Holland composer team, showing up in classical only. I will agree that he IS classic Motown though.