It functions-ish for me. It works on macOS(10.15.2) as expected but iPadOS will show the SSO pane and allow me to login but afterwards touch input of any kind is gone. Rebooting the device allows me to proceed through any remaining setup assistant panes. I'm going to try a text pane next to see if it's just the SSO pane with the issue.
After rebuilding my VMs (10.15.7 and 11.1) - they are now picking up the Enrollment Customizations.
Seems if you are just turning on Enrollment Customizations and testing, you need to rebuild your VM. If you've had Enrollment Customizations for some time now, they just work. What I'm confused about, is why isn't the payload deployed per enrollment? Seems like it is somehow dropped off prior to enrollment.
One unexpected consequence of enabling Enrollment Customizations for our environment - it allowed the users to change their password post-LDAP AD authentication (we have a JIM Proxy for AD auth)
Prior to enabling - the users skipped the Account Setup screen and their credentials were locked to their account. They couldn't change them. With enrollment customization enabled, they are now able to modify at the account setup screen. Not cool for us.