Override of WS-Federation Form Template not working


We have a tenant using classic login with a custom template and our web app has custom markup under Applications → → Settings → Advanced Settings → WS-Federation → Form Template. This custom markup is never used, only the default one with a completely blank page (to an unknowing end user) and the javascript submit. We need to be able to have this page tell the end user be patient while we are logging them in, now it just looks like it didn’t work and they can press the back or reload buttons which in turn will ruin the login. Is there a setting somewhere to enable this markup?