Hats!

The last two times I have  simultaneously baked two boules I have run into an odd problem. I have a baking stone in my oven.   When I  bake two boules one of them gets cooked in a combo cooker and the other directly on the baking stone covered initially by a cloche (the bottom part of my cloche broke so I'm just using the top).  The loaf cooked in the combo cooker comes out looking normal. But the loaf baked directly on the baking stone is coming out in the form of a hat with a brim. This has happened to me twice now, but I didn't previously have this problem cooking on the baking stone. This bread is Levy's French Country Mutigrain, from a recent edition of Bread Lines. I increased the hydration by 2% because when I made this before it seemed like it needed more water. The dough ended up quite wet and it was difficult shape. So the hydration may have something to do with this, but then I didn't have this problem with the loaf cooked in the combo cooker. Any ideas what might be going on here? ( The bread is delicious. )