I have one like this, she's been an indifferent feeder from the day I brought her home at 250 grams. She'll eat 2-3 feedings in a row then stop for a few months. She's a 2013 and hasn't hit 1000 grams yet. She's in a rack with other ball pythons, her temps and humidity are fine, she has a proper hide, etc.

I've found that feeding her every other week helps her be more consistent, if I push food every week she fasts for longer.