David and Ash (for those who already watched Covenant)

Nice point, @Ashtekar. It's interesting to see how the crew of the Nostromo would never take Ash for a synthetic if not by the order 937 and the following events. It makes me to think about David's personality in Alien:Covenant - a lot more human and emotional, and so a lot more convincing while acting among humans. In the first scene, we see a very robotic David interacting with Peter Weyland, look how much he has 'evolved'. That damn movie gave us a lot of new questions unanswered lol

David -> Walter -> Muthur -> Ash

I think David's personality it's inherent in his programmation. Walter said that the David model was so human that discomforted people and David replied to that saying that Walter had lost his capacity to formulate questions or being creative. Walter disagrees with David about the Alien and it's capacity to destroy life forms and I believe that David it's unique on thinking that way (I mean his internal code). For that reason is that it would not be surprising if David could manipulate Muthur in some way or if at some point David interacted with Ash (reading some information from muther?) but there is a hole plot on that because weyland changed the internal code of future models but if you think in weyland being like an actual tech company, the fact that they released other robots doesn't mean that they could recycle "programming code" from the previous versions, maybe the answer could be a "glitch"?