In 397, Lü Guang sent his brother Lü Yan (呂延) on an attack against Western Qin, but Lü Yan was killed in a trap set by the Western Qin prince Qifu Gangui.
By 401, however, Duan Ye was heavily apprehensive of Juqu Mengxun's strategies and abilities, and he considered sending Juqu Mengxun far away.