What?!! This makes no sense. Two versions available at the same time - and with no clear indicator of which version the customer is actually buying on the box?
If you buy the movies on Blu-ray, you get the Blu-ray versions of the films.
If you buy the movies on Ultra HD, you get the Ultra HD versions of the films on both the UHD discs and the BD discs.
Just like when the Blu-ray box sets included the Blu-ray versions of the films on both the BD discs and the DVD discs. So there’s already been a precedent for this.