Building off of what jarbear said - I think with Han, Han was always kind of snarky and cranky to everyone, and you could tell that 3PO in particular actively annoyed him (cockblocking him with Leia, complaining about his flying). With the new gang, it just feels like they don’t care about him either way. Like, Han treated him like an annoying coworker - he was still a presence with a personality; the Trio just treats him like a soulless machine.
That said, I can’t think of any moment that really seems as callous as when they decide to go to Kijimi. If anyone else is interested, it may be worth it to try and play with that scene, see if anything can be done.