Message being sent as CHEXMSG instead of MSG

I am sending a message to my ESP32 using the chirpstack API, when I send the message using Postman it is received on the device as +MSG however when I send through my backend (uses the same endpoint and same body) the message shows up in the queue the same as Postman however it is received on the device as CHEXMSG, anyone know why this happens?

It is not really clear to me what the issue is and if this is ChirpStack related. The sending of messages to your ESP32 is probably done by your device firmware. So what you need to figure out is what the payload difference is between the two methods of downlink scheduling. Maybe the payload is the same but you are using a different fPort?