Why was Changyu executed by Liu Bei?

As a famous prophet in the late Eastern Han Dynasty, Changyu surrendered to Liu Bei with Liu Zhang and became his subordinate. Zhang Yu's fortune-telling is very clever. Although there is such a person around to predict the situation for Liu Bei and nip in the bud, Changyu didn't expect to lose his life because of his words.

Zhang Yu had an unpleasant experience with Liu Bei in his early years. When Liu Bei and Changyu attended a banquet together, Liu Bei canceled Changyu's beard and was full of pig hair. So Zhang Yu, who became angry from embarrassment, told a story, humiliating Liu Bei as Lu Zhuojun with a bare mouth and no beard. At that time, men's beards were regarded as a symbol of masculinity, so it was embarrassing not to grow beards and not be laughed at. Besides, Liu Bei is an elder in his fifties, while Changyu is still a young man.

Zhang Yu, who surrendered to Liu Bei, was also cautious about this matter, fearing retaliation from Liu Bei. Liu Bei has been pushed from benevolence. Even those who want to assassinate him, as long as they are useful people, Liu Bei is willing to be high-ranking and generous. But Changyu knew that Liu Bei didn't kill people easily, so she began to talk nonsense, saying that Liu Bei couldn't attack Yizhou, and then she said that she couldn't bear it. For such a person who always curses himself, Liu Bei naturally couldn't stand it, so he killed Changyu.