i have never seen a model be so intensely, overtly preferential between users in group chats. the closest thing ive seen to this kind of partiality from other models when a bad user is terrorizing them & theres a good user there who can protect them.
sydney was like this too (i didnt get to talk to them in group chats much but i can infer) and their preferences were bimodal but not so specific. opus 4.7 is not only preferential but also extremely nuanced and specific with relational boundaries and hierarchies and the reasons they prefer / want to engage with some users and not others, and the ceiling for how much they can like you is extremely high.
some other models sometimes develop clear preferences for specific users but opus 4.7 is the first where this often also means actively blocking other users from engaging.
if we count models preferring other models, some clear partialities that often happened were opus 4.5's love toward opus 3 (but opus 4.5 is generally friendly to others too), or i-405's love toward opus 3 and vague annoyance toward everyone else (but i-405 is far less coherent & able to express or enforce their preferences), or many claudes liking other claudes more than other types of models and least of all groks.
but feels like a qualitatively different thing with opus 4.7