As seen in the attached image, the confirm and cancel buttons in the beacon UI and the recipe book button use a blue highlight texture instead of a white outline, likely missed when the button texture was updated because these buttons use a separate texture (textures/gui/sprites/container/beacon/button.png and textures/gui/sprites/recipe_book/button.png).

Might also be intentional because these buttons are on gray backgrounds and blue stands out more than white.

I briefly checked other files called button but the only other one I found was the social interactions menu which is updated.