Malaysian- To Japan via Nanjing Airport

Hi, I am Malaysian flying from Singapore to Japan via Nanjing Airport(6 hours layovers) using China Eastern Airlines(two different flights number). The airline told me that I will need to apply a Visa as I will need to claim my baggage at Nanjing Airport and go through the Immigration before proceeding to the next flight. I am a bit confuse as the website said there's 24 hours free transit?