Songs from a various artists album are not correctly identified by artist when played back



If I say "Alexa, ask Plex to play the song XXX" and that song is part of a compilation with the album artist set to "Various Artists" it replies that is is playing the song title by various artists, and not the artist of that particular song (even though it is set correctly).

Am I doing something wrong here?
Just tried it on a song in Now that's what I call music 86, where all the files are correctly ID3 tagged, and show correctly in Plex with the correct artist.

Also, if I say "Alexa, ask Plex to play the album Now that's What I call Music 86" it plays volume 34, even though I can see in the Alexa app, it herd me perfectly well..

Every time I try and use Alexa to try an play music from Plex, i get increasingly frustrated with it, and end up shouting at it (which doesn't help at all!!)

Please help me understand what i am doing wrong here, or is is just broken?