live desktop system booted with ip=dhcp has the right lease, hostname not set at all

Here the cmdline:

vmlinuz initrd=initrd rootfstype=nfs netboot=nfs nfsroot=162.38.151.26:/exports/focal-desktop boot=casper ip=dhcp fsck.mode=skip automatic-ubiquity url=http://162.38.151.26/preseed/fds/focal-efi.seed

File /run/systemd/netif/leases/2:

# This is private data. Do not parse.
ADDRESS=162.38.80.32
NETMASK=255.255.248.0
ROUTER=162.38.80.1
SERVER_ADDRESS=162.38.87.254
NEXT_SERVER=162.38.151.26
T1=7200
T2=12600
LIFETIME=14400
DNS=162.38.151.23 162.38.151.24
NTP=193.51.157.3
DOMAINNAME=fdsetu.infra.domain.fr
DOMAIN_SEARCH_LIST=infra.domain.fr fdsetu.infra.domain.fr
HOSTNAME=focal-uefi
CLIENTID=0152540071e1f2

But the hostname is still the default one "ubuntu"

$ hostnamectl
 Static hostname: ubuntu
       Icon name: computer-vm
         Chassis: vm
      Machine ID: cbb8d889829d4e2594ab55a53749e7e9
         Boot ID: c93c8cc26fa040f6b010077e676bf7ec
  Virtualization: kvm
Operating System: Ubuntu 20.04.2 LTS
          Kernel: Linux 5.8.0-43-generic
    Architecture: x86-64

It should be "focal-uefi".
I had the same issue with ubuntu server autoinstall

See https://bugs.launchpad.net/subiquity/+bug/1905932

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: systemd 245.4-4ubuntu3.4
ProcVersionSignature: Ubuntu 5.8.0-43.49~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-43-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
CasperVersion: 1.445.1
Date: Tue Mar 23 15:30:42 2021
LiveMediaBuild: Ubuntu 20.04.2.0 LTS "Focal Fossa" - Release amd64 (20210209.1)
Lsusb:
 Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd QEMU USB Tablet
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Lsusb-t:
 /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
 /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
 /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
 /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/6p, 480M
     |__ Port 1: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 480M
MachineType: QEMU Standard PC (Q35 + ICH9, 2009)
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
 LANG=C.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: vmlinuz initrd=initrd rootfstype=nfs netboot=nfs nfsroot=162.38.151.26:/exports/focal-desktop boot=casper ip=dhcp fsck.mode=skip automatic-ubiquity url=http://162.38.151.26/preseed/fds/focal-efi.seed
SourcePackage: systemd
SystemdDelta:
 [EXTENDED] /usr/lib/systemd/system/rc-local.service → /usr/lib/systemd/system/rc-local.service.d/debian.conf
 [EXTENDED] /usr/lib/systemd/system/user@.service → /usr/lib/systemd/system/user@.service.d/timeout.conf

 2 overridden configuration files found.
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/06/2015
dmi.bios.release: 0.0
dmi.bios.vendor: EFI Development Kit II / OVMF
dmi.bios.version: 0.0.0
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-q35-3.1
dmi.modalias: dmi:bvnEFIDevelopmentKitII/OVMF:bvr0.0.0:bd02/06/2015:br0.0:svnQEMU:pnStandardPC(Q35+ICH9,2009):pvrpc-q35-3.1:cvnQEMU:ct1:cvrpc-q35-3.1:
dmi.product.name: Standard PC (Q35 + ICH9, 2009)
dmi.product.version: pc-q35-3.1
dmi.sys.vendor: QEMU