@ Kyrill It's not really an error. In China's imperial and upper class harem system tom old times, all recognized children were officially children of the main wife, regardless of whoever birthed them. When Meng Yao became Jin Juangyao, he became the son of Madam Jin on that technicality, no matter how infuriated she was about his existence, and he was obligated to call her "mother" no matter his actual feelings towards her.