Maybe something to do with the vm?
Could not reproduce.
With 6.6 LTS plus one custom kernel;
$ ls -a /boot | sort
.
..
amd-ucode.img
efi
grub
initramfs-6.6-x86_64.img
initramfs-linux-amd-znver3.img
linux66-x86_64.kver
memtest86+
System.map-6.8.9-AMD-znver3
vmlinuz-6.6-x86_64
vmlinuz-linux-amd-znver3
And grub looks normal during boot, etc.