POSSIBLE SPOILER
I think Shanks turning away from Harold like that with the shading over his eye portrays that he is undercover, and he finds what he is saying distasteful. And Harold looking back at Shanks is a "isn't he a pirate"cor "what's he up to?" Look. That's my interpretation.
This may be the start of seeing how he obtained the Nika fruit or something.
Yeah my initial thought was that he was uncomfortable or smt. I'm keeping an open mind maybe he really did have an evil arc (considering he also met up with the five elders before egghead went down he might still be working for them...) but idk I don't think shanks is a genuinely bad person
Considering shanks still has both his arms this is before he met luffy and thus before he stole the gomu gomu no mi right as the world government had it. Either he's infiltrating them or he experiences smt that makes him betray them
On the other hand, justice for loki