I installed 5 s50pro’s and 4 a50+ in my home and everything works great. When i group all the zones together to play the same music, when i play with the volume levels it lags to change volume and gets louder and lower as if it is going crazy. My home network has 3 switches connected with 10gb optical connection and all devices with lan are on a 1gb speed. So its not a lagging network issue. Any ideas why?