NAD M33 won't play 88.2KHz 24 Bit with roon?!?

I think you can believe Bluesound if they say it’s their problem to fix. It may well play fine with BluOS and still have a bug with Roon, nothing particularly impossible about that.

Also, two posts up I linked the post with Bluesound’s response, and just a few posts up from that one there was a post by Roon: