Description of problem:
In the past a kickstart partition of:
part pv.2 --size=11776 --grow --asprimary
volgroup vg00 pv.2
logvol / --fstype=xfs --size=5120 --name=root_lv --vgname=vg00
logvol /boot --fstype="xfs" --size=512 --name=boot_lv --vgname=vg00
Would work, and result in a bootable system. Now this does not work, likely due to more rigid /boot checks to not be on lvm.
This should be "undone" slightly, to allow /boot to be on lvm. Grub2 fully supports this, and allows post install lvm raid setups to take place that are very useful to system administrators.
There's a RHEL 8 bug for this with some RH customer demand, but the current story on it appears to be basically "it's not possible". Still, I'll leave it up to anaconda team to decide whether to keep this open or not.