What is going on at HP? All of my legacy calculators, HP 12/15/16C and 41CV worked consistently where the X register is the most current value entered and the operation 2 enter 3 y^^x was always 8. Prime treats the most recent value as Y, a break from tradition. At least the swapped button matches but the Y register threw me. And yes, 2 enter 3 x^^y on the Prime still calculates 8 as well.