Oh, that's interesting! Yeah, it must be the translator's go-to insult: Volume 1 of the official translation has 10 instances of "dumbass" or "your dumb ass". Zhao Yunlan applies it to Zhu Hong, Lin Jing/the team generally, Wang Zheng and Da Qing once each, and he thinks it about Guo Changcheng three times and says it aloud to Guo Changcheng once. Chu Shuzhi/the narrative implies Guo Changcheng is one, and Da Qing calls Zhao Yunlan "dumbass" once. /literature survey ;-)