Nobody is saying 300 is normal. We are saying that you probably have 2oil temperature sensors (engine oil temperature sensors). 1 sensor for the ECM and 1 sensor for the gauge you keep taking pictures of. If the oil temperature sensor that operates the gauge is bad, or the circuit is grounding out then you will see a temperature reading like you are seeing. This would explain why you see the dash gauge reading 300 but the ECM does not log a Fault Code because the ECM see's the 2nd oil temperature sensor.