I can manually configure my Raspberry Pi model 3B-plus on-board
wired
Ethernet port to operate. It is indeed only DHCP configuration that
fails, but only with the on-board device; DHCP configuration of a USB
wired Ethernet port works fine.
Have you tried the 4.16.0-300 kernel that's in (or on it's way) to
updates-testing?
Works fine, Peter Robinson. Thank you.