It is pretty normal for a chicken to eat a broken egg. I don't consider that egg eating. It's when a chicken has learned to purposely open a good egg that I consider it a problem. In all my years of keeping chickens I've had one egg eater though I've had several that will eat a broken egg. Not all do but a lot will.
Pullets like yours that are just starting to lay sometimes lay weird eggs. They might be soft-shelled, no shell but just a membrane, double yolked, no yolk, tiny, thick shelled, or weird in other ways.
Often when pullets start to lay they pick out a nest and lay there. But sometimes it seems the egg catches them by surprise, they don't know it is coming. They drop it wherever they may be, on the roost at night or just walking around during the day. Once they gain control of the egg laying process they should always lay it in the same spot, hopefully your nests but not always.
The egg laying process is pretty complicated, both in putting together a good egg in their internal egg making factory and the behaviors of egg laying. Sometimes it takes a while for a pullet to work out all the kinks. It's kind of surprising how many get it right from the start.
It is possible one has already learned to open a good egg to eat it and the others rush in to share the bounty. What sounds more likely to me is that you had one drop a soft-shelled or shell-less egg in the run and it broke. You may have a problem, but I'd give it time to see if it is a pullet laying soft shelled eggs.