So we all know about ED-E vanishing, and a lot of people saying that if you go back to vault 22 and use the elevator he'll come back. I tried it, didn't work. Well yesterday i had Veronica as a companion but i accidently made her wait in Cannibal Johnston's cave. I went to vault 22 to find a skill book, used the elevator to floor 5 and who was waiting for me there.....Veronica! WTF?! Still don't have ED-E back btw.

There's a bug with the elevator, no matter where you have left your companion they'll show up with you if you use the elevator.

If a companion glitches out of the game there may be no way to bring them back so the elevator bug won't work.