Ive noticed that my new MacBook Pro 2018 15inch is making a very minimal crackling/ static fan noise. you don't hear it when the fan is blowing so much. but when the fan is not on full force and just on low I could hear the very minimal crackling/ static noise. its not always there and its not loud where you can hear it, unless you really pay attention and put your ears close. it sounds like static I would say? I just wanna ask if its normal that it have those sounds?