The command in Lina's hand was not personally issued by Kenji. In fact, Kenji had no idea about this matter. The reason she could enter the Murong residence with a document bearing Kenji's seal was that Kenji had previously given her and Siyue blank documents pre-stamped with his seal.
Once there was a need, they could simply fill in the content. This seemingly absurd action contained a great deal of trust in his sister and his guard. Siyue and Lina did indeed live up to this trust. Faced with the issue of the Murong residence, Siyue decisively chose to verify the matter with the Chancellor and General Balinos. After obtaining the Chancellor's signature, she used Kenji's blank document to fill in the content and then began a thorough investigation of the Murong residence.
Obviously, Linas Murong of the Murong residence was extremely angry about this thorough investigation.