gdm smartcard login and gsettings banner-message-enable problem

I've configured the RHEL 8 workstation for gdm smartcard login. It works. When I insert my piv card, the gdm login screen changes to a single box prompting for my piv pin and I am logged in after entering my pin.

However, I need to set the login screen to display a banner. I've done this by setting the following gsettings keys:

disable-user-list=true
banner-message-enable=true
banner-message-text=...banner text...

After running 'dconf update', the banner appears. But when I insert my piv card, the screen no longer changes to the piv prompt screen.

I've tried a variant keeping disable-user-list false. Now the banner no longer appears and the piv prompt no longer shows up when I insert my piv card.

Not quite sure how to debug this. First question is if this is even possible.

Hints?

Thanks.