 In 777, Li briefly left military service to observe a mourning period for his mother.In 778, he was recalled to military service and commanded the forces of Bin (邠州, in modern Xianyang, Shaanxi), Ning (), and Qing (慶州, both in modern Qingyang, Gansu) Prefectures, and he participated in repelling another Tibetan incursion.It was said that at this time, there was an incident during Guo's absence that Li wanted to forge an imperial edict to execute several senior officers, including Wen Ruya ().