The idol appeared on a radio broadcast on January 30 when he was asked about a fun place to visit while traveling to Jilin, China. Renjun accidentally called Baekdu Mountain by the wrong name, calling it Jangbaek Mountain (Changbai) instead which is what Chinese people usually call the mountain. Chinese people call it this because of the Northeast Project of the Chinese Academy of Social Sciences. There have been diplomatic disputes between China and Korea about the project due to its claims on Gojoseon, Goguryeo, and Balhae, trying to incorporate Korean history into its own.
By calling it Jangbaek Mountain, he is indirectly saying it is a Chinese mountain.
There is much debate about whether or not Renjun is wrong in using the name Jangbaek Mountain. In addition, the name is controversial as it was used in the past by China to support unifying neighboring countries into China. Netizens have been commenting:
"Then can, Japanese people call the East Sea, the Sea of Japan?"
"Leave the group and go back to your country."
"If you're going to work in Korea, learn Korean history."
"Go home, Chinese person."
Others defended Renjun, claiming that in Chinese school, he would've learned the mountain's name as Jangbaek and the airport for tourists to visit the mountain is even named Changbaishan Airport.
Renjun is Chinese nationality but it is rumored that he is ethnically Korean.