Hi guise!

Well, first, let's say
Thank you Obsidian for finally bringing us a Fallout worthy a predesecor of F1 and F2.

Then now for the bug,

I'm on my second play trough and figured I'd be an evil guy, swooping and twatting what comes in my way, so naturally I choose to side with Caesar's Legion whoem eventually give you a quest

==== spoilers =====
There is a NRC cpt. that is really with the legion, and legius sends you to him to see if you can do any work for him, quest is called:
I Put A Spell On You.

Now, since I'm evil and vilivied by the NCR, getting in their HQ isn't a smart idea in my regular atire, hence I killed some NCR at the base and stole their shirts, dressed up like them, succesfully allowing me to roam Camp McCarran.

It is discribed in the help that obviously, higher ranked officers can see trough your disquise. And mister Captain can indeed. So, even though the Legion loves me, where his allegiances lie, he starts attacking me and the questline dies with him ;(
==== end of spoilers ====

Well, that's my 2 cents, keep up the good work Obsidian!

Oh it's on the PC btw.

As far as I know, it's not a bug.
It's stated that guards can recognize you through your disguise.
Same thing happened to me in another quest, I had to be creative but pulled through.

its not a bug not only can guards see through your disguises
when you are caught trying to impersonate someone else your are automatically attacked

Yes, this is not a bug. If the Gaurds look closely enough, and being Villified is grounds for close inspection, your disguise will fail.

And, here is the bug list

http://www.gamesas.com/index.php?/topic/1141352-bug-list/