Lol I actually just had another one today where I was doing a mission on Neon and told my companion to wait in one of the air ducts because she kept alerting the guards when I was trying to sneak around. I totally forgot about her in there and during the next mission I was talking to an NPC and my companion interjected with something... from a totally different floor, partially obscured by shadows of an air vent she was standing near. Gave me a good laugh imagining her standing in a dark air duct for hours and then somehow hearing our conversation from multiple floors below us and giving her thoughts on it.