Every now and again I'll take Ed-e or Rex with me some place that is populated by friendly or neutral npcs. They will then commence with attacking random people for no reason. This happened in the casino in Primm as well as the sewers over by north vegas. It's even happened at Hoover Dam once. Anyone else get that?

i did wit ed-e in the casino in primm...i had to put ed-e down myself before he killed my quest givers and exit the casino.

I think this question was actually answered a while back. Actually ED-E aren't losing it their defending themselves. The AI of the NPC sees food[including water] on ED-E or Rex and decides the only way to get it is to kill them. Because they are flagged as creatures and not NPC's this is considered "legitimate" behavior. The next patch will fix this bug but until then its adviced you remove food/water from their inventory. And of course one NPC in town gets in a fight and suddenly there all in a fight.

This.

ED-E gets into fights all the time with the locals in Westside or in the sewers, and almost always with the Quartermaster in Hoover Dam (he fought him 3 times out of 4 when I was in that room, prompting me to leave him outside the Dam doors. Also, he gets stuck in there a lot, I feel). At first, I thought it was just a glitch that caused him to attack, but then I realized that it was usually the NPCs who fired or swung first.

BTW, Boone and ED-E wiped out most of the settlers/citizens of the New Vegas sewer system. One of them attacked ED-E, and then he and Boone got into it with everybody else, while I tried to find the exit. Got lost and ended up in a running battle through the sewers.

I am suddenly experiencing this as well. My last play through, Ed-E and Boone were left on the Legion home base, and as one would expect, 7 game days later they returned to their respective homes.

Well, I went to get Ed-E, zoned in to John's house in Primm and Ed-E starts attacking John and his wife. Ed-E kills John, and I kill Ed-E. I reload from my last save, and go in again, surely enough, Ed-E attacks John again... So I decide to leave Ed-E alone for that playthrough, as I was about to do the Mr. House path finale.

A few days later, I feel ready to do another playthrough, create a new Courier, and start up... I get up to level 6, get about 1/2 through REPCONN Testsite, and deside to go get me a companion or two. Go get Ed-E first. Repair him with parts, and head over to V & V to sell some stuff off to John...and Ed-E starts a firefight inside V & V Casino.

So I reload, repair Ed-E again, this time I head south to Mojave Outpost...arrive at the outpost, and here we go again, Ed-E cant keep its laser cool...starts shootin at a Crimson Caravan Merchant...

What gives??? The first two play throughs I did didnt have this problem. Crashed a lot, er, hung/freeze-ups I mean, but no glitched killer eye-bot ever before...

Edit...

I just read someone's reply as to a probable cause...I will check it and reply whether the behaviour changes when I offload the campfire crafting (if ya wanna call it that) items I had stowed on Ed-E...

Thank you LV...this was indeed the answer to the issue in my case...

I did search for Ed-E issues and could not find the post you're referring to, but in any case, thank you again for reposting the answer to the question.

You do know that Rex doesn't like people with hats right? The King told you that when you take Rex from him.. The NCR and quite a few NPC's wear hats - so Rex attacking them isn't that unusual. As for ED - well IMO he's just broken (a patch might/could fix him - but I'm not holding my breath on it)