My Harman Kardon speaker is wireless connected to one of my Deco x20 devices. When streaming audio from my smartphone this speaker stutters sometimes, while the other speaker (HK soundbar) keeps worki

I use five Deco X20 devices. It seems that when my phone is connected to the same Deco-device as my wifi-speaker/chromecast, casting does not work. When my phone is connected to one of the other Deco-