Basically it sounds to me as if you are "cooking" the dish way too long after you have added the rice. I add the rice last, after the veggies are the right texture for my taste and then dump the cold, at least day-old rice in, quickly break up and stir in the veggies as you add soy sauce and as soon as the rice is heated, remove from the pan. It should still be separate grains and "fluffy". I do a LOT of stirring for this dish.