You are feeding 150 grams rats when she eats, that's too much. Feed smaller prey if you want your animal to eat with more consistency.
The only animal here that get 150 grams rats are 3000 grams and over.
Feed smaller once a week rather than bigger once a month.
As for the weight loss it depends on when you weigh your snake and 100 grams on an animal that size can easily be a bowel movement.
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