Might be something about how Deezer;s CC communication is not playing nice with the B&O devices.
I just tried CC'ing from the Qobuz app on my iPhone to my BS2 / A9 - and they both worked fine.
So seems to be OK with Qobuz, CC and the B&O speakers I have,
No help to you of course, but just passing on the information.
Did some more Deezer testing on this lazy Sunday.......and it seems the Deezer app is not casting ANY GC product anymore, not to the B&O, not the HK and even not to the Google Home, Mini and Nest devices......and those Google products have the latest GC versions (1.5y.xxxx). Seems a problem of the Deezer app maybe (new version since end of January......)??