On the NV scope in the LAV-25, (as was the case with nighttime filmgrain around version 1.5/1.6) the filmgrain is not scaled with internal resolution, meaning the size of each grain becomes disproportional larger on smaller screen resolutions.

For better explanation, take a look at the two screenshots I have attached, one at 1080p and one at 1440p. The smallest grain spot/pixel should be the same relative size of the screen (or the sight ranging lines) regardless of resolution, but its not. For illustrative (not to scale) purpose, it could be described as a low resolution having 1 pixel of noise covering 3 arcsmins (≈1 milliradian) of view, where as on larger resolutions, the same 1 pixel of noise covers only 1 arcmin (≈⅓ milliradian) of view. Notice how many pixel grains there are on each image along the 5 mil lines horizontal on the sight on the 2 different resolution images.

Because the grain is supposed to be an artifact of the NV tube in the scope itself, there should be the same number of grain pixels regardless of resolution (e.g. 1000 grain spots on the screen's Y-axis, scaled to fit any resolution screen, kind of how UI elements like sight-picture/crosshair is displayed)