I resolved the issue, as suspected the Domain Controller was running DHCP services that present a problem to the link. This shouldn't be an issue, but I guess the device software isn't expecting UDP packets on Port 67 and it tears down the link. There must be a vulenarbility that creates a denial of service type response.
I'm not sure why there was any server broadcast as there were no new client DHCP requests and DHCP is strictly a server respond to client request only service, so maybe there is also an issue with Windows Server 2016's implementation of DHCP, it wouldn'tbe the first Microsoft IP implementation issue.
It should be noted that running more than one DHCP service on the same IP network is entirely legal (for redundancy) & there is a protocol to handle Server to Server Communication, so only one server responds to the client request.
Unfortunately I don't have time to go through syslogs at this point & I guess it would be beyond the scope of this forum anyway.