I think I remember Azealia implying Miley is appropriating African Americans (which is true)
Something like that and then Miley shaded her back with something like "I don't see Jay Z talking about you bitches in his songs" and then Azealia said something along the lines of "I wasn't even talking about you but if the shoe fits"
I'm not sure about what exactly was said but that's a summary of what went down