Why the OpenShift cluster node's log file is full of network and/or NetworkManager related errors?

Issue

• Logs are full with errors like below;

Mar  4 08:51:23 HOSTNAME NetworkManager[12047]: <info>  [1551689483.7833] device (veth7cbfa439): state change: ip-config -> failed (reason 'ip-config-unavailable', sys-iface-state: 'managed')
Mar  4 08:51:23 HOSTNAME NetworkManager[12047]: <warn>  [1551689483.7841] device (veth7cbfa439): Activation: failed for connection 'Wired connection 14'
Mar  4 08:51:23 HOSTNAME NetworkManager[12047]: <info>  [1551689483.7842] device (veth805e75ba): state change: ip-config -> failed (reason 'ip-config-unavailable', sys-iface-state: 'managed')
Mar  4 08:51:23 HOSTNAME NetworkManager[12047]: <warn>  [1551689483.7851] device (veth805e75ba): Activation: failed for connection 'Wired connection 15'
Mar  4 08:51:23 HOSTNAME NetworkManager[12047]: <info>  [1551689483.7858] device (veth2053a28f): state change: failed -> disconnected (reason 'none', sys-iface-state: 'managed')
[...]
[...]
Mar  4 08:51:24 HOSTNAME dhclient[101337]: DHCPDISCOVER on veth0ba653a6 to 255.255.255.255 port 67 interval 15 (xid=0x68905e2c)
Mar  4 08:51:24 HOSTNAME dhclient[101333]: DHCPDISCOVER on vethebb059c9 to 255.255.255.255 port 67 interval 13 (xid=0x7309a962)
Mar  4 08:51:24 HOSTNAME dhclient[102158]: DHCPDISCOVER on veth23ea0140 to 255.255.255.255 port 67 interval 7 (xid=0xe83ade4)
Mar  4 08:51:24 HOSTNAME dhclient[101144]: DHCPDISCOVER on vethfbd216ec to 255.255.255.255 port 67 interval 14 (xid=0x3712bd3e)
Mar  4 08:51:24 HOSTNAME dhclient[101199]: DHCPDISCOVER on veth39eb5d05 to 255.255.255.255 port 67 interval 8 (xid=0x276adf62)

• As per these logs, it looks like the NetworkManager is trying to get DHCP address on the vethxxxx interfaces which ideally it should NOT manage.