Fedora 35 & 36 cannot find kickstart partition by label

I’m working on installation procedures for Fedora 35 on a new computer build and have run into the following issue. I’ve also tested it against the current F36 development image and it occurs there.

I’m booting the Fedora 35 Everything/x86_64/os/isolinux/{vmlinuz,initrd.img} installation kernel and trying to specify a kickstart file with the kernel arguments. My kickstart file is on the third partition of my NVME disk with partition label LDC and an xfs filesystem.

This works: init.ks=hd:nvme0n1p3:/install/kickstart.ks

This does not: init.ks=hd:PART=LDC:/install/kickstart.ks

I’ve tried several other variants (different disks, filesystems, etc) and none seem to work specifying the partition label.

Is this a bug? The docs say it’s supposed to work. Cf. Boot Options :: Fedora Docs Or am I just doing something wrong?