I'll also ask for a photo of the nest and where they are laying. Sometimes we can see something that helps. It sounds like you have pullets that have just started laying. It could help to know a bit more about that history. Was the nest open a few days before you saw your first egg? Did you have a fake egg in that nest?
The egg making process is pretty complicated and involves more than just putting the egg together properly. It also includes knowing when and where to lay it. Some pullets know the first egg is coming, maybe as much as a week ahead of time. They start looking for a good nest so they know where to go when it happens. I like these pullets.
But some don't see that first egg coming or it comes at the wrong time. If the timing is off they may drop it from the roost at night. That doesn't seem to be your issue. If they don't expect it they may drop it wherever they happen to be, just walking around in the coop or run. If you find eggs scattered around that's probably what's going on. When you find the eggs consistently in one place they have decided that spot is their nest.
Many seem to like to lay where another hen is laying. Not all do but many do. That's why we often recommend you put a fake egg in a nest to show them where to lay. I use a golf ball but some people use a wooden or ceramic egg. Some people use those empty plastic Easter eggs, maybe filling them with something to add weight so they don't get scratched around as much and taping or gluing them closed.
Now to my guesses and speculation. It is possible that first pullet decided the spot next to the nest makes a good nest. They don't always choose our nests. Different hens or pullets seem to like different things when they are looking for a suitable nest. You just don't know what is going on in her brain. If the first pullet selected that spot the second may have said, "Looks good to me too". So that's theory #1. Theory #2 is that a pullet accidentally dropped her egg there and decided "That will do" so she keeps going back.
So what can you do? If you haven't done it yet put a fake egg in the nests you want them to use. You can use a real egg but that egg might go bad over time, might accidentally get broken in the nest, or might attract an egg eating predator. I like fake eggs better. Sometimes that works.
Don't allow any eggs to stay anywhere other than your nest so they are not showing them to lay in the wrong place. Try to collect them often. That's easier to do if you are around during the day than if you are gone.
If you find a pullet on that nest don't let her lay her egg there. You don't want her to think that is a good safe place to lay. If you can, catch her and put her in a real nest. She may not stay but at least put her in there. I made a couple of my nests so I could lock a hen in there if I need to. That's come in handy for a few things. I lock them in that nest until they lay their egg, usually about a half hour.
I've tried blocking off where she is laying to force her to lay somewhere else. That's never worked for me, they just lay beside what I use to block that area. But your location may work better for that.
Another option may be to accept that as a good nest and let them lay there. You could even build another nest and put it there. I don't know how well that would work out for you.
