Hi @Warren_Wilcock,
So we can better assist you, please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
What kind of content are you playing? Streaming content (TIDAL or Qobuz) or local content? Where is your local media stored?
If you play to System Output of the Core machine does the same behavior occur?