Hi @John_Dickerson,
Thanks for sending those logs over! According to the logs, it looks like your System Output zone only supports 6 channel content: "supported_formats":"48000/16/6".
Can you please try to open the Device Setup tab for this zone and change the Channel Layout to 5.1?
You’ll also want to enable Send stereo/mono content as 5.1 so that all the content gets set to the appropriate channel rate before output.
Let me know if this helps!