I'm using pve 5.4 and get this problem
root@pve:~# patch /usr/share/perl5/PVE/QemuServer/Cloudinit.pm < cloudinit.patch
patching file /usr/share/perl5/PVE/QemuServer/Cloudinit.pm
Hunk #1 succeeded at 49 with fuzz 1 (offset 12 lines).
Hunk #2 succeeded at 149 (offset 12 lines).
Hunk #3 succeeded...