Ah, I simply assumed you applied to the strain tensor (which you input to the deformation generator).
I varied my kpoint mesh from 1000 to 3000 and didn’t see a significant shift. I don’t have access to VASP, but I can try a different code. I still have no idea what is causing this issue in any case. Oddly enough, calculating Carbon (diamond) does work sufficiently well…
I tried to vary my shear strain ranging from 3% to 8%. I have no difference in my shear elastic elements after I reach about 4%. If I go lower it drastically drops by more than 15 GPa.