I kind of went through a similar situation as you, but I was the one underfeeding my ball python. My first BP was getting one live mouse every 1-3 weeks when I first got her. She was only 700g in March (and that was after feeding her f/t rats for a few weeks in a row). She started pounding rats until about mid July. She got up to 1800g and just decided she was done. She stopped eating unless I gave her live mice. I don't feed live because I can't reliably get to the store each week. I basically waited her out and now I only feed her f/t small rats. My theory is that they will pound food and put on weight quickly, but when we let them do that they are more likely to go on fasts because they have been eating so much.

Snakes can go long periods without food as long as it is their choice. I would watch her weight and keep offering her the f/t rat. I had a juvie ball python go on a 2.5 month hunger strike and come out of it about the same weight that she went into it and I tried everything, even live ASF.