Relatively new to bread making. I have become fixated on making a whole wheat sandwich loaf, and this is the second time I have tried a similar recipe. The taste is good, 80% whole wheat with a little honey and some oats. Both times I have made it though, the loaf isn't smooth on top. It gets holes. Is this a sign that it is over proofing? Or is it possibly too little kneading? Something else?