From what I have been told, they are having problems activating the update feature on the samsung pay. I have a support ticket in with them on it, and they are going to call me back. (They did already once). The support person said that it is widespread, and its a beta thing. Their system verifies that you are eligible for the beta, then activates and update/install button IN the actual pay app. That system is the one not working. Once the system goes open they check to see if your eligible for the beta will be gone, and so will the problem.... or so 1 rep says.
As for the check for updates... (its the top button in that screen) there have been no updates released so far for the note 5, so that is just a precautionary step. No update (from that system) is necessary to participate in the beta.