In the quest, the NCR captain asks you to go visit 'Keith' to see if he is dealing drugs or something else. When you go in there with ED-E, the junkies aggro on him and him only..(or maybe ED-E aggros on them?)

So I had to reboot and told ED-E to wait outside.

So I went in and found evidence against Keith

Came back with the captain to arrest the guy..didn't think it would be a issue to have ED-E, but alas the captain open fires on ED-E, the quest is then un able to complete because the Captain goes back outside..and still wants you to find keith's evidence of wrong doing..and you already have found keith's wrong doing ugh.