Did you (ex/) pwBPD speak shit about people behind their backs and still have them as friends?

My expwBPD has one solid friend and she still used to speak so much shit about her behind her back - calling her fake, calling her a "bullshitter", had a massive ego and said things like "Oh she took 2 days to reply. Now I'm gonna take 2 days to reply", said mean stuff about her, AND STILL invited her to her place, had house parties, etc.

Ever since we broke up, she seems to be clinging onto her. Just funnily weird how she goes from that to this. It's sad that her friend doesn't know about any of this. Did you ever observe that?