After the structure data contains 0x0020 or 0x000C and is sent, the receiver cannot receive the data packet

[mumu2021]

// Report the key data structure
struct KeyData {
PacketHeader header = {CMD_KEY_DATA,version}; // Set the command type
char pinName[5]; // Pin name
char pinValue[8]; // Key name
uint8_t pin; // IO
uint8_t keyCode; // HID key code
uint8_t type; // Key status
};
When I assign the keyCode of this structure to 0x0020 or 0x000C, each time the sender sends data, the receiver will trigger two callbacks. However, the length of each callback data packet is 0. The AI tells me that 0x20 and 0x0c might be the packet protocol data segments of the library.
May I ask how I should solve it? thank you