A pair of ONE speakers looses all sound when added to a group.

I am streaming through WiiM box connected to line input on PORT. Grouping several components; couple of MOVE, PLAY1 etc. Normal operation. Until the two ONEs in the kitchen: no sound just some very low bass. 

Cross-check: the ONEs produce normal sound when streaming through Airplay or directly through services in the controller app, in single as well as in group.

Can’t be any settings on the WiiM-box or PORT as sound level is normal on all other components.

Suddenly, no recent changes. Other than a wifi password change couple of weeks ago that has turned out to be a pain. Sonos components are not able to handle a plain simple password change and had to reset the entire system several times.

Yet another of those inscrutable Sonos issues?