Why is Renshou Hall in the Summer Palace just a rolled-up gray tile? Not glazed tiles?

If Renshoutang doesn't have a rolled roof and grey cloth tiles, it's not normal. The administrative space in the royal garden is different from that in the palace. As for Paiyundian Group, it is an exception. Its predecessor, yanshou temple, was ridged and covered with yellow-green glazed tiles (which was in line with the practice of religious architecture in the royal gardens of Qing Dynasty). During Guangxu period, the Summer Palace was rebuilt into a group of Paiyun halls, which are still ridge-shaped and covered with yellow glazed tiles.