Fix ESP32 MQTT Memory Leak

I'm looking for expert on memory leaks with MQTT on an ESP32 to refactor the code to prevent memory allocation errors.

Freelancer must have platformIO, an ESP32-S3, and an MCU to communicate with the ESP32-S3 via I2C.

Candidates must answer this interview question. Why does the following code have a JSON parse error with free(msgBuffer), but not without?

// Helper to push JSON into send queue
void queueIotMsgToPublish(String jsonPayload) {
if (sendQueueHandle != NULL) {
char *msgBuffer = (char *)malloc(jsonPayload.length() + 1);
if (msgBuffer) {
strcpy(msgBuffer, jsonPayload.c_str());
if (xQueueSendToBack(sendQueueHandle, &msgBuffer, 1000*portTICK_PERIOD_MS) == pdPASS) {
// Serial.println("IOT: Queued msg to publish");
} else {
Serial.println("IOT: ERROR publish queue full");
}
}
// free(msgBuffer);
}
}


// MQTT Receive Task
void processMqttMsgFromQueueTask(void *parameter) {
char *msgPayload = NULL;
for (;;) {
if (xQueueReceive(recvQueueHandle, &msgPayload, 10*portTICK_PERIOD_MS) == pdTRUE) {
if (msgPayload) {
String msgStr = String(msgPayload);
uint32_t length = strlen(msgPayload);
// Serial.printf("IOT: Rx length %d \r\n", length);
Serial.printf("IOT: Rx %s \r\n", msgStr.c_str());
JsonDocument msgJson;
i2cCommPacketStruct MsgPacket;
DeserializationError err = deserializeJson(msgJson, msgPayload);
if (!err) {
// Process Message from IotCore

} else {
Serial.print("IOT: JSON parse error: ");
Serial.println(err.c_str());
Serial.println(msgPayload);
}
}
}
vTaskDelay(2);
}
}