Roon not Ungrouping Sonos zones

Using several current (Sonos S2 app compatible) Sonos devices in various zones - Sonos SL’s, One’s, Port, Play 5 Gen 2, Amp). This all works very well, and grouping works well, but ungrouping not so much - ungrouped zones still play stream from Roon. I can go into the Sonos S2 app and ungroup the Roon controlled drives, and this works. Minor inconvenience. Any thoughts?