Thank you itimpi for your prompt response, I've swapped the docker network to ipvlan as suggested. Hopefully that is it!
Today's shenanigans had pinned all my array devices to full read speed, while it was doing a parity check, and make the whole gui unresponsive. I couldn't stop the parity check from command line, nor export diagnostics. It was just locked up. Does macvlan just cause havoc to all things when it goes bad, or is it normally just related to network issues?
Thankfully syslog server has saved today's events, which I attach.
Thanks again for your help so far, it is appreciated.
syslog-192.168.1.10.log