Egg color is hardwired in the DNA, so a hen who lays blue eggs will always lay blue eggs, and a hen that lays brown eggs will always lay brown. A few factors can vary the color of the egg, including the intensity of the bloom, which can make blue eggs look green, or brown eggs look pink or speckled with white, and eggs that are laid early in the hen's cycle will have the most rich color, but they won't change back and forth between two entirely different colors. I don't know who's laying what, but unless you have a chimera, your chicken simply can't lay two entirely different colors of egg in her life--her genetics won't allow it.
Do you have any other chickens in your flock? If you have caught both EE's in the act of laying and they are both laying blue/green eggs, then the pink eggs are coming from somebody else. If you only have the two EE's and no other chickens, then one of them is laying the blue/green eggs, and the other EE is the one laying pink.
