My youngest rabbit for a long time now has shown nothing, but aggression to me since she was 3 weeks old. I’ve had her since she was born and rehomed her siblings, but not her because I had grown so attached even if she did seem really mean. She is bonded with your mom (and I mean correctly bonded not they cuddle sometimes. If I seperate the they try to escape to each other, they cuddle together, they groom each other, they’ll even bring food to each other like strawberries which grow in their run). The mother is fixed. The baby is not due to a heart problem, fixing her could put her in more danger than leaving her intact. She’s attacked me for several months and finally now that she’s about 7 months old, she allows me to hand feed her and pet her with no signs of aggression. In fact she runs up to greet me as soon as I open her pen door. I hand fed her daily and now only pet her from above or the sides. She doesn’t like anything in her face and I had not realized this before. 
We still have one tiny problem. She has anxiety attacks anytime I pick her up and if I hold her for too long she kicks like crazy. Her father (who I also adopted. I took all of them in from a small breeder who tried to give them away as meat. I wanted to rescue the father and pregnant mother) also does this, but only if held improperly. He is fixed as well now. The mother could care less. She’s my floppy baby. I don’t think this is a trait from her parents and I can’t figure out how to help her, if there is even a way to. Can anyone help??? I just want her to be a happy bunny 