toxic

so I have this friend that I'm pretty close to and I would always help her with friendship trouble she has been having. but recently she has been coming to me a lot because of a toxic friend she has and she has complained a lot to me about how she is childish, plays the victim and just toxic. and she kept on saying how she isn't going to be friends with her because she's toxic. but recently I keep on seeing her saying how they are best friends and it just confuses me, cause a second ago she was talking bad about this person and saying how she doesn't want to deal with her anymore and now she is posting best friend tiktoks and tagging her. maybe they talked about it in private and it's not any of my business what they do. it just feels like I'm there only for her to talk bad about this person and then suddenly she is best friends. it's not about me and I'm probably overthinking this.