For OP’s situation, she knows the tone and the people involved… so in that case probably “You are so dressed up” could a put down. Or it could be them feeling insecure … less likely though when the majority of the gang dresses casually.
Just want to point out I think sometime people (including me) sometimes say vague things doing a last minute pivot on a possibly inappropriate comment. Example - “You look so pretty today” could be the initial statement intended, changed on the fly so as to not talk about appearance.