Leaf growing below the rockwool cause mold?

I got some clones recently, and I quarantined this one because I was concerned about a leaf growing up from below the rockwool. My concern is that the humidity is very high between the leaf and the rockwool and will cause some kind of fungus, perhaps powdery mildew? I am wondering if anyone has any knowledge on this?

bumpity bump

I wouldn't worry about it . Your roots are down there . If you continue to leave that block exposed to the light , you might get some alge. It won't hurt anything , just look ugly green .