Not currently any consolation for you, but as Hyundai have rolled out an update for earlier cars, knowing that later cars are also affected, there must be a reason they haven't issued an update across the board.
I'd guess one will appear for later cars in the fullness of time. By issuing a fix (hopefully) Hyundai have acknowledged there is a fault, so I'd hope dealers will now stop moaning and charging about doing regens for customers.
Manufacturers are constantly altering parameters/settings in their cars, that we, the consumer never get to hear about. It's quite likely that cars built after March 2021 came out of the factory with a different ECU programme to those that came before, so they've worked on a fix for earlier cars, but haven't yet sorted one out for later cars. These things take time and money unfortunately.
