The beta does indeed now limit the tracks within an album to the selected genre / composer.
However, if I may use the same post, another observation that appears inconsistent.
I selected a composer with compositions within three albums. So far so good.
I chose to random play these compositions via the random play button next to the composers name.
As hoped for, the queue contained only these compositions in a random order.
(btw - I think the selection of random play within groups of tracks is a brilliant idea)
But, select an album containing the composers tracks, of which there are less than in the whole album, selecting random play results in the whole album being queued.
Admittedly, the random play button is next to the album name and is probably correct but not what I hoped for.
Further, select an album, as above, select one of the tracks results in that track and the remaining album tracks, regardless of composer, being queued. I would have hoped for just the composers tracks in that album to be queued.
Not sure how useful doing any of that is, in practice, but having chosen a composer, presumably to listen to their tracks, the appearance of other tracks seems incorrect.