After the change to using a Customization window to set weapon and armor stats, the stat selection window is bugged for exotic and ascended weapons (but not legendary weapons). All of the available stat combos from approximately HoT onwards show up stacked together at the bottom of the window, and none of the stats can be selected. However, the core stat combos show up correctly. I tested this with several exotic weapons that previously had all stat combos in the game as selectable stats, and also tried setting the stats in Core and PoF maps to see if it was related to the current location of the character. I don't think it's intentional that only legendary weapons can allow stat selection from HoT/PoF/LS stat combos. Will this be addressed in a future update?