Systematically tries to connect to wifi at startup even though ethernet cable connected

There's a WiFi network to which I sometime connected and saved it and set it to automatically connect when available; however the password was changed, so whenever my laptop automatically tries to connect to that network, I get the prompt to enter the password. So far all expected.

What is unexpected is the following:

What I do is:

- plug my laptop to the office LAN via an ethernet cable
- turn on the laptop

Expected: after boot, the computer should connect to the wired network, and hence not attempt to connect to the WiFi network

Observed: every single time I boot, 100% systematically, I get the prompt that says that it couldn't connect to the WiFi network and asks me to enter the password manually. The popup shows up even before I log in (usually even before the login screen shows up, when part of the screen is still a mess with random garbage presumably from the uninitialized GPU memory).

This most likely means one of two things: either the network manager attempts to connect to the WiFi network before it checks the wired network (by the time I dismiss the prompt the wired network is already connected), or it attempts to connect to WiFi even though it is already connected to the wired network.
Either way the behavior is wrong.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: network-manager 1.2.6-0ubuntu0.16.04.3
ProcVersionSignature: Ubuntu 4.4.0-166.195-generic 4.4.194
Uname: Linux 4.4.0-166-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
ApportVersion: 2.20.1-0ubuntu2.20
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Nov 15 16:20:10 2019
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2013-10-11 (2225 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
IpRoute:
 default via 192.168.1.1 dev eth0 proto static metric 100
 169.254.0.0/16 dev eth0 scope link metric 1000
 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.37 metric 100
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.NetworkManager.NetworkManager.conf: [modified]
mtime.conffile..etc.NetworkManager.NetworkManager.conf: 2015-02-20T16:52:59.722501
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 eth0 ethernet connected /org/freedesktop/NetworkManager/Devices/1 Wired connection 1 662a0c09-71a8-4101-9236-ebcc1696d69a /org/freedesktop/NetworkManager/ActiveConnection/1
 wlan0 wifi disconnected /org/freedesktop/NetworkManager/Devices/0 -- -- --
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/2 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.2.6 connected started full enabled enabled enabled enabled enabled