I watched an old "Judge Judy" today. At some point she asked the opponents if they were still friends. It brought to mind a question my mother used to ask when I said something negative about a friend of mine. She would ask if we were "bad friends". My understanding was that if we were, it meant more like "friends having a bad day" Rather than that a friendship that was over. Has anyone else heard the term? Would you agree with my definition?
I've seen no evidence that it is a phrase or expression in use. It seems like nothing more than your basic adjective - bad friends are simply friends who are of low quality or are bad for you in some way.
The way your mother used the combination - directly asking you "are you bad friends" - actually does sounds like a phrase, a punny spin on "good friends," which can very well mean "friends having a bad day."