FOV Related Lighting Issue/Bug

[The Civ]

So far, DOOM has been almost entirely free of visual bugs, at least for me, so once I noticed this issue, I can't stop seeing it every time I play.
For whatever reason, it seems that the lighting on gun models is tied to the FOV, even though the size of the gun model itself changes only very slightly with the increase of the FOV.
Therefore, increasing the FOV to anything above the base 90 ends up creating several cutoff points for each light on the gun, said cutoff point being where the light would end on what it assumes is the end of the screen, so it seems that for some reason, increasing the FOV, actually scales the lighting as well.
This can most prominently be seen below on the Combat Shotgun, and on the BFG 9000, where the lighting is cut off below, and on the right side of the light source, rather than fading out as it normally would when the FOV is set to 90.





This issue seems like it would be a simple fix, but then again, I have no idea what the inner workings of idTech 6 are like.
It's only a minor visual problem, but since playing with the FOV set at anything below 110 is disorienting for me, it's just a tad annoying.