I tried to change a light bulb in my house the other day and saw the screws holding the light fixture on the ceiling were rusty. I also noticed the post holding the dome cover was rusty too. I assumed the homebuilder (house is 3 yrs old) might have just used old hardware for this light. But I have found rusty hardware in multiple lights. In fact, I just noticed today, that one of the posts had rusted so bad that there was a pile of rust dust that had collected in the bottom of the dome. It was a surprising amount. now I am worried I have a problem in my attic, like my bathroom fan is not venting and my attic is full of humidity. I am going up in my attic shortly. Any thoughts on what is going on?