I have this exact same problem. It's never stalled my weight loss, but I've fallen off the wagon EVERY time. Some days I would only get 500 calories, some days I might get 700, some days 1000, then on a binge day I would eat 3000 or more. Then I'd have a week full of binge days. That's why I'm still up here, hovering around 200lbs, looking down at my goal from a looooong way off.
Now I don't know if this is directly linked to my shortage of calories. I know that the common advice around here is to try to stay around 1200 calories, but everyone's body is different. This time around, I'm getting up around 1000 every day, sometimes going over, sometimes I get all 1700, but it varies from day to day and I'm losing at a nice rate. Not the 3 lbs a day I would lose when only eating 600 calories, but I'm glad for that, because I really really want to stick to it this time. But I totally understand how calorie counting can make you eat way under. When I start watching what I'm eating, I watch it very closely. It's as if, once I'm made aware of how many calories I'm actually consuming, I become hyperaware, and restrict more than I should without making any effort to do so.
It's mostly still a mystery to me