Some time ago raised this issue and was unable to resolve it: basically
a MINT installation set up with a static interface using network
manager, seemed to be registering itself with a pingable DHCP assigned
address *as well*. This address re-registered itself with the DHCP
server on a regular basis.

After eliminating all the alternatives of something else on the network,
and various bits of the networking subsystems - of which there are many
and various in a modern distro, I ran out of time to investigate.

And Lo! it came to pass that the Lords of Mint deigned to issue an
upgrade to 20.2, and the server having been shut down by a thunderstorm
induced power failure, it seemed to be a good idea to upgrade to the
latest release, and Lo! When the server was booted, it came to pass that
the network manager item was crossed out, and said it was not working,
and yea verily the interface was up on the statically assigned address,
and moreover although the server had indeed requested a DHCP address on
boot, this address was no longer pingable by any other machine on the
network, and 22 hours since boot, the DHCP lease has not been refreshed.

Question: If I were to uninstall network-manager would it still assign
an IP address?

I have killed nm-manager and the greyed out icon has disappeared...

--
“it should be clear by now to everyone that activist environmentalism
(or environmental activism) is becoming a general ideology about humans,
about their freedom, about the relationship between the individual and
the state, and about the manipulation of people under the guise of a
'noble' idea. It is not an honest pursuit of 'sustainable development,'
a matter of elementary environmental protection, or a search for
rational mechanisms designed to achieve a healthy environment. Yet
things do occur that make you shake your head and remind yourself that
you live neither in Joseph Stalin’s Communist era, nor in the Orwellian
utopia of 1984.”

Vaclav Klaus