Advice please!: ex friend talking about my baby?

So this girl was one of my close friends and one time she babysat for me. My daughter was 6 weeks old at the time and it was her first time away from me so understandably she cried a lot of the time. Since then that girl and I had a falling out. We worked together so have lots of the same friends. Apparently some other girls were talking about how cute my daughter is and she couldn't help but say the only time she saw lily (my daughter) was when she was crying. This isn't true at all and it's not the first time I've heard her say something rude about my now 7 month old child. I'm in mama bear mode and ready to rip her a new one but it would cause unnecessary drama. What would you do? Let it go or tell her off? (Note: if she said stuff about me I wouldn't care, it's only because it's about my child)