We have just measured the shape of the crater that the returner landed on, which is part of the scientific data collection. Then the returner will [put on a] 'new warm coat' to prevent the remaining propellant inside from being frozen during the transportation to Zhurihe Airport, where the propellant will be expelled from [the] returner," said Cao Ruiqiang, a space product assurance assistant, in a China Central Television interview (1:29-1:35).
Why should the propellant avoid freezing? Cooler generally means slower chemical reactions, so safer. There may be a language barrier here, but the propellants on the returner (lander) may have been hypergolic. Apollo's hypergolics tolerated temperatures colder than those at Chang'e's landing point.