The Green Forest had seized thirty grain transport ships bound for the Cui Family in Qinghe. Naturally, after the seizure, the Cui Family of Qinghe would demand the grain from the Grain Transport Service.
At the time, Ling Hua had just been married in the Capital City for a few days and could not rush to Caojun. The only option was for Cui Yanshu to return to Qinghe to deal with the situation. Because of this, he was too busy to pay attention to his household affairs, and with the Eastern Palace taking advantage of the chaos to cause trouble in Caojun, it led to the opportunity for his younger cousin Zheng Zhenyu to be taken by Cui Yanyi. He was spread too thin to take her back.
This was a series of strategical moves and the foregone conclusion of Cui Yanyi's collusion with the Green Forest.