We're only talking the icon for the althud rather than the main weapon display, right? That sprite actually has the yellow line on it (as do most of the frames of the Strife Guy's hands). For the weapon graphic it should be hidden below the bottom of the screen (and is as far as I can tell) Presumably the reason you see it on the icon at that resulution is because it's high enough resolution to show a bit more detail - which includes the yellow line. At other resulotions the line probably just gets lost when the sprite is shrunk to be the icon.
I definately understand what that yellow line is all about.. it seems rather inconsistant that you don't see it when you are not using the Widescreen mode feature (same res).
And yes, it is the Alt Hud.. which is obvious from the image.
Yes, it does only seem to be the widescreen aspects. However, I can see it in almost all the widescreen resolutions. It seems only the lowest WS resolutions do not show it. My guess as to why it happens still stands though.
If you don't like it notthing will keep you from fixing that sprite and use ALTHUDCF to reference the copy. I won't fix this because it would disable any eventual replacement sprites for this weapon.
Actually, it is much better than PNCHA0. I'll add this to the default ALTHUDCF lump. But that still doesn't make this a bug. Whatever Rogue thought by adding that yellow line - it was just stupid.