Tile roofs with a #30lb.felt paper base and a #90lb.hot asphalt installed underlayment system is installed and the tiles adhered using mortar add extra weight to the system. During hot months the roof temperature rises above 160 degrees softening up the asphalt adhesive. With the extra tile weight and without enough fasteners to hold the tiles to the deck cause sliding tiles, especially on high-pitched roofs. There is no way to repair this issue. However, it is a sign that replacement is near.