When I aim a gun at a NPC or Monters in combat mode they change color into a bright red purple color. Anybody know how to fix this problem???

You have boone as a follower?

Yes I do. I am not sure if it happened before i had him. But yes right now i have him as companion.

That's his spotter perk you are seeing then. It's not a bug, it's Obsidian's idea of a feature

Im sorry but i never realized this? So the change in color once you aim is suppose to help you? Dont you feel it is a little annoying? So the glow like christmas tree, really helps?

It's helpful if you're sniping targets far away and can't see them very clearly.
He spots enemies for you, making them stand out so they're easier to target.

If you're not even sniping and just fighting people at close range, it's not much help.

Yeah I wish it was something you could toggle or something that only turned on with scoped weapons. When you use it with those weapons though- oh man is it useful. I've been going to snipe someone at extreme range with the anti-materiel rifle and because of boone's perk was able to notice and snipe the two people nearby as well who were otherwise blending in with a shrubbery. Needless to say, there wasn't even a chance for them to say "ni."

Limiting it to (or making it an option to limit it to scoped weapons) would make it make more sense too. I mean that's what a spotter does- helps the sniper adjust his aim and provides information on adjusting for things like wind. They're not shouting "over there" in the midst of a close quarters fire fight. They help find and identify targets for sniping. I would be able to accept the perk not working for weapons that aren't really something you can snipe with. Not like I'm going to need wind speed and ranging information while blasting away with an SMG or a shotgun right?

Maybe if people let their voice be heard they can put it on a patch. That only long range weapons use that perk. Its really silly to have to use it on your shotgun.