It looks like the shell cracked when it was in the oviduct, but was sealed again. This can sometimes happen when a chicken is stressed out, if the oviduct just experiences a fluke, or if the bird is a new layer. It probably isn't anything to worry about.
Interesting! Thanks for the response. She isnt new to laying and I really doubt she is stressed, though just came out of a molting period last month so maybe thats it. I will keep an eye out just in case.