On what will be the bottom surface of one of the cherry desk tops I'm building, there is a knot hole. Roughly 3/4 in diameter and 5/8 or 3/4 deep in the 1" thick top. There is no sign of the knot itself on the top surface except for the circular grain pattern you would typically see near a knot. I've pressed on the area above the hole with a dowel and no sign of flex or weakness. It won't show on the bottom surface unless you climb under the desk, so my thought is to just leave it be. But I could fill it with epoxy if there is any reason to do so. I can't think of a reason, but thought it was work asking here. Fill or not?