I've had a case where I kept the female in a breeding trap while the male in the tank was working away building a nest. I could see the female was plump and full of eggs but wasn't sure when to release her. After a few days, she started just dropping her eggs and devouring them as they dropped. At that point, I quickly released her and the breeding process went along as expected. So I guess, when the female is egg-laden but cannot breed, she will drop her eggs anyway. And since they are so nutritious, its better to eat them than to let them rot away