Comment 7 for bug 1779721

The dhclient lease looks ok. It has a largish MTU, but that should be fine.

Does the dhcp server in question require MAC based client identifiers?

Could you please try:

network:
  version: 2
  renderer: networkd
  ethernets:
    all:
      match:
        name: ens*
      dhcp4: yes
      dhcp-identifier: mac

Note the additional 'dhcp-identifier: mac' key.

Failing that, a package capture using wireshark inside the guest would be needed; under systemd-networkd, and again under dhclient. Packet capture should reveal what sort of things systemd-networkd is doing different to dhclient.