Mine is also broken. Spent some time on chat with Samsung and they told me it was my use of the Nova launcher. Contacted Nova and they have a ton of info to point out for Samsung what it is that's blocking the full function of Pay with alternate launchers. I tested other launchers, and it's not just Nova, it's Go, Apex, etc too. My understanding is that something checks whether it's the Samsung launcher being uised and if it isn't, it's killing off the open session of Pay, and that removes the gray swipe-up bar and fingerprint shortcut actions.
Going to send on the info from Nova to Samsung. It's annoying enough for me to quit using Pay in favor of using the Nova launcher, sadly