Thank you for providing that additional information.
A 192.168.1143 IP address for the node is not a valid one, I beleive you meant to write 192.168.1.114, which is a valid one. 192.168.4.119 is not in the same subnet as the router, so I would expect this lookup to fail. You mentioned that you got the logs of the Node, would you mind sharing those with me? I could not locate them in the dropbox link you provided.
I recall that you said that the Bluesound is plugged into a couple of power strips and purifiers, but how is it connected network-wise? Is it on WiFi or Ethernet? If it is on WiFi, can you try connecting at least one of them on Ethernet and let me know if the same issue still occurs?
I looked up the Techicolor router and these types of routers are listed in our networking best practices as needing some special settings to be applied to them to properly work:
We’ve seen that some technicolor routers cause Roon to have difficulties communicating to networked endpoints. This can be resolved by adding exceptions for Roon and RAATServer to the router’s IPv6 firewall settings.
Can you give this a try and let me know if that changes anything?