According to lanlingfeng, Zihan was cruel enough to leave Chu. He knew the real identity of Chu, so he decided that the doll was put by Chu.

but lanlingfeng knew her identity soon after Chu entered the palace. The palace guarding sand of Chu's palm betrayed her. Zuiyue palace has always only accepted female disciples, and all female disciples will be ordered on the palace guarding sand after entering the palace. If people in the palace communicate with each other secretly, the Palace guarding sand will disappear. It is said that if zuiyue palace disciples betray their teachers and people's private life, then the first child she gave must be...