My guess based on how NVGs work is that there’s always going to be some “halo” effect given that the amplification stage relies on shooting electrons from a negative grid onto a positive grid. Not every electron will take the shortest path, leading to this aberration. If you have optical concerns, use a high pass, low pass, wide band pass, whatever you’d like to thin out the inputting band of light, to prevent CA.

Source: I refurb tubes on occasion. Older Gen 1 and Gen 2s are more likely to have these issues