The more animal you own the more likely you are to own a true picky eater that will eat every once in a while.

I used to have a female that would eat once in a great while, small rats every 3 to 4 weeks if I was lucky, she had always been like this ever since I got her too, of course she grew very slowly and will never be a huge animal, she was 1200 grams at 5 years old when she laid her first clutch (6 eggs), since laying she has been eating like a horse and eats every week, maybe breeding triggered something in her metabolism who knows?

So yeah it happens.