Bluesound Group relative levels change in Roon

I have a Bluesound Group set up in my office comprising a POWERNODE (330) driving the front speakers and 2 Pulse Mini in stereo pairing mode (+Pulse Sub) acting as rear speakers essentially in a multi channel stereo setup.

In BlueOS I have set up the relative sound levels between front and rear to be optimal to my listening position at my desk. However, whenever I use Roon and select this group, the relative sound levels change. Often the front channels (from the POWERNODE are muted or very low) and the rear channels and sub have been boosted to ridiculous levels.

I can go back to BlueOS and readjust the balance (front to back) but the next time I use either Roon or BlueOS after listening (via Roon in the pevious session) the levels jump around again. If I do back-to back sessions in BlueOS only, the levels remain as they should.

Roon is being served by a ROCK from an Intel NUC.

Anyone got any ideas as to why Roon is altering the levels?