An incident involving Gao Cheng soon threatened to undermine not only his position as Gao Huan's heir apparent but Princess Lou. In 535, Gao Cheng was discovered to have had an affair with Gao Huan's concubine Zheng Dache (鄭大車). Gao Huan was so angry that he caned Gao Cheng 100 times and put him under house arrest, and also refused to see Princess Lou. At that time, his favorite concubine was Erzhu Rong's daughter and Emperor Xiaozhuang's former empress Erzhu Ying'e, whose son Gao You (高浟) he now considered making heir apparent to replace Gao Cheng. Only at the intercession of Gao Huan's friend Sima Ziru (司馬子如) -- who first reminded Gao Huan Princess Lou's contributions to his success, as well as Lou Zhao's, and then forced the main witness to the affair, Lady Zheng's servant girl, to commit suicide—were Gao Cheng and Princess Lou able to remain in their positions. Still, Princess Lou and Gao Cheng submitted themselves to humiliating apologies to Gao Huan, where they knelt at each step as they approached Gao Huan after Gao Huan went to see them. After the incident, however, Gao Huan appeared to continue to honor Princess Lou and turn to her for advice. For example, in 537, in the aftermaths of Gao Huan's defeat against Yuwen Tai at Shawan (沙苑, in modern Weinan, Shaanxi), the general Hou Jing suggested making an ambush against Yuwen's own camp; it was Princess Lou who advised Gao Huan against such action, noting that if Hou actually captured Yuwen, Hou would never return.