I have a tried and true banana bread recipe I've used many times without fault. However, this time I cut a banana in half and placed it on top before baking for two separate loaves. After my usual cooking time, the bread was cooked all around, but raw batter directly underneath where I placed the banana slices. I thought maybe it was a problem with the moisture of the bananas preventing the batter to cook, but other recipes with this decoration don't adjust at all and seem to have no trouble, what am I doing wrong??