Is the Gem of the Grand Prophecy actually no longer available? As far as Morganthe's drop list on the wiki page goes, the ice amulet seems to be the only one missing...
That being said, a comment on the May 2022 Update mentioned that the amulet itself got nerfed, but I can't seem to find ANY information on what the supposed nerf is or any update about the amulet.
One is for level 99 (retired). This the original one. The second is listed as level 100. This is the only one that drops now. You can compare them there. And yes, it was badly nerfed, two weeks before I got it. The athame was also nerfed.
The athame was also nerfed.