Rice cooker problem: film appears after cooking
It is perfectly okay to eat. I am going to assume when you cook rice, the rice comes out a bit too moist. The "film" is literally the water and the starch from the rice that has dried and turned into a thin film of rice starch.

If you like your rice the way it currently is, then there is nothing to worry about. But if it indeed is too moist, then decrease the amount of water you use to cook the rice.