Madam Xi had always perceived Qin Yan as a manipulative woman. She felt that Qin Yan must have tricked her son into being with her in such a short time.
She was really upset by the matter. If it wasn't for Old Madam, she wasn't going to readily accept Qin Yan as her daughter-in-law.
She would never let them be married. She was never going to let such a manipulative woman enter the Xi family.
Hence, since she was prejudiced against Qin Yan, she naturally thought that Qin Yan was vicious and her actions had hidden agendas.
They were just acts that showed how manipulative she was. It was like the saying "If you didn't like someone, you would find fault in everything she does."
She hated Qin Yan even more after she saw Old Madam and her sons supporting her. She had already created so much trouble in the family in such a short period of time. Who knew what other tricks she had up her sleeve?