So ok, one strange bug is every so often for no apparent reason one of my companions will start fighting with a non-hostile NPC. The first time it happened, it was Rex and some people at the 188 trading post. I didn't see it start, I just heard gun fire and ran up to see everyone shooting at Rex, and a caravan guard dead on the ground. They knoced Rex out, then it all went back to normal. At that point, I just figured maybe the first guy Rex attacked was wearing a hat, and he ended up killing someone else before they took him out. But just now, ED-E, and Fantastic at Helios One, just started throwing down for no reason. Luckily, Fantastic ran away before ED-E could zap him to death. It has to be a glitch, because they didn't start fighting until after I had been hanging around that area for a little while, and no one turned red on my radar (so it wasn't anything I did).

Another bug, that is SUPER annoying. I am trying to do the quest where you fix up the Helios One Power Plant for the NCR (who I am in excellent standing with) and one of the Terminals I have to access is surrounded by guard dogs that are red on my radar and attack if I enter the fence where they are kept. If I fight back all of the NCR troops, who before were kissing my butt, start shooting at me.

This happened to me as well. I am not sure if you tried this but, you can use a stealth boy to get past the dogs and activate the terminal. As far as official fixes I am not sure.

That second one is real weird. I'm on my second play through and never had anyone go hostile when I killed those dogs, even though they are NCR dogs. My first time through I was nearly idolized by NCR. On my current (2nd) play through I'm aligned with CL and still no one went hostile after I killed those dogs. Try using a silenced weapon when killing those dogs. IIRC both times through I was using a silenced varmint rifle to kill em, that may be why no one went hostile.

Yeah, I did that. Also, with a little luck you can just run really fast and dodge around the barricades. Got through without getting bit and closed the gate behind me.

I'm actually starting to wonder if this isn't a glitch. Since the other terminal has mines and other traps around it, maybe the NCR just keeps a bunch of really mean ass dogs in that cage in order to keep people out. That's the problem with NV, there are so many bugs that sometimes it is hard to distinguish between what should and should not be happening.