As you are growing Indoors, and your plants are growing big and dense, the light has not the chane to get everywhere. To the light exposed branches are more ripe than the others. But its no problem. If it comes in direction to harvest, You can harvest in stages. At first the ready ones and then in stps the rst of the plant. If you cut away the ripe ones, the other branches have a serious chance to get more light and to maturate.