Anybody able to help with a problem with my Play 3’s, used as surrounds with a Playbar and Sub on my TV? 
 

The Playbar is connected to the TV using optical cable, sub added and play 3’s running as left and right surrounds. The TV set up works perfectly.

When I play music on the same system, from about 3 seconds to 12 seconds of each new track, the system stutters, as if it’s trying to sync all of the players. After c12 seconds, it’s settles and plays the whole track. If you skip to next track, it stutters again.

i have un-linked the Play 3’s and removed the sub. The Play bar works perfectly on its own. Add the Sub and again, they work perfectly. Both Play 3’s work perfectly on their own and also work perfectly when connected together as a stereo pair. 
 

Bizarrely, when I group the play 3’s as a stereo pair with the playbar and the sub, they also work perfectly. But, if I reconnect the play 3’s as surrounds, the stuttering returns when I play music through the system.

i have many other players throughout the house and have no problems with them. The system is using the Sonos boost and I’m getting c160 to 300 mbps depending on the time of day with FTTP.

im running the system without the play 3’s connected as surrounds currently but it feels like a fudge. Any help greatly received