Both the original Sphairai and Kaiser Knucles have their "handle" too far back and as a result they don't fit like gauntlets as intended.
This problem was resolved with the versions released in Stormblood (Sphairai Ultima and the crafted palette-swap of the Kaiser Knuckles) but unfortunately the original models weren't also updated. I imagine it would be an easy fix since the correct skeletons for the models already exist in-game.