LG MH653 Series Owner's Manual page 33

When operating the microwave oven, If you use a product such as radio, TV, wireless LAN, Bluetooth, medical equipment,
wireless equipment etc. Using the same frequency as the microwave oven, the product may receive interference from
these products. This interference does not indicate a problem of the microwave or the product and is not a malfunction.
Therefore, it is safe to use. However, medical equipment may receive interference as well, so use caution when using
medical equipment near the product.
After cooking is complete, the fan may operate to cool the oven.
The display will show 'Cool' . If you open the door or press once
STOP/CANCEL before the cooking time is complete, the remaining
cooking time will show on the display. This is not a malfunction.