This issue is not specific to our company's machine model. Any device with an RJ45 serial port will exhibit this phenomenon.
The server has abnormal keyboard input
Initially suspected BIOS or HDM abnormality. Reflashing the version and powering off for 10 minutes failed to resolve the issue. The keyboard still had abnormal input. Later, it was discovered that the on-site engineer plugged the network cable into the serial port, causing continuous signal input to the serial port, resulting in abnormal print input from the keyboard.
Unplug the network cable from the serial port and the problem will be solved immediately