Comment 2 for bug 1958260

A similar sounding issue was reported on focal: LP: #1901464, but lacked the /proc/cmdline.

Another issue that may be related:
    https://bugs.launchpad.net/cloud-initramfs-tools/+bug/1766723

There are also changes in 0.47ubuntu1 that may address this issue, that might be worth considering backporting.