Found the issue.
Hi RobOnLI, Thanks for the PM with all the details. We've researched this, and have found the issue. The good news is that your NW Worldperks number was in your reservation the whole time. You hadn't been EUA'd because F/C simply wasn't available. The bad news is that online check-in failed to recognize that your Worldperks Elite number was in the reservation, which is why when you entered it, it treated you like it was never there.
Our Technology group is going to get this fixed asap, but in the mean time, next time you check in and don't see your Worldperks number on the screen, be sure to re-enter it. Even though it's already in there, by re-entering it, you'll be sure to get on the upgrade standby list, EliteAccess on your boarding pass, etc.