I also have the distortion problem with firmware 867 v1.41. tested with Qobuz and two different 24 bits - 96 kHz files.
Tested both casting via the Qobuz App and DLNA - UPNP streaming via the Music Life App.
After a minute or so the distortion kicks in.
I asked my dealer for an official statement from Arcam about an expected resolution for this issue.
If there is no resolution within 2 months from now I will return my SA30.