I have noticed this as well. I have several duplicates in my library (I have no Tidal or Qobuz) - for example one copy of an album which was purchased on iTunes (AAC) and another copy of the same album which was ripped from a CD (ALAC). I will “Hide” one (say, the AAC) but still see both when I am looking at the albums for the artist.
I found it quite confusing to mark an album as Hidden but to still see it listed. In addition I don’t see any indication that the album has been marked hidden.
It might actually be nice to see - or be able to toggle into a view which would reveal - hidden albums on this screen. But to simply keep showing albums that were marked hidden sure seems like a bug to be squashed!