The following tree doesn’t render well:
Classical > Classical Period
- Symphony
- > Choral Symphony
- Concerto
Both Symphony and Concerto appear as subgenres under Classical Period - as expected
The issue comes with Choral Symphony, which appears as a direct subgenre under Classical with the name Choral as well as under Symphony.
This feels like it could be the same issue which os causing Baroque Pop and Rock Opera to appear under the Classical genre with accidental partial matching.
As an aside on this though I wonder whether the 3 genres affected here (as well as others) Symphony, Choral Symphony, Concerto should be made to “go away” by the app in the main browse view and any music with these as genre instead regarded just as “Classical Period” with the genres used instead to provide additional info to apply the form in the classical view.