It looks like the spar is just slightly curving up at those three ribs, Check for an opening at the bottom of the notch(under the spar) in each rib and fill it with glue to improve the joint. if you find the same issue on the other panel, you may be able to press it down with a little bit of weight. I often use plastic bags filled with sand. Take your time and enjoy the build. Many of us(myself included) started with the Eagle kit, so someone can answer pretty much any question you dream up.