Coolant temp sensor issue or air pocket?

This could be a couple things. It could be a temperature sensor, an air pocket that is moving through the system, or the thermostat.

If it were me, I monitor the voltage on the sensor and make sure it is moving in relation to the gauge. If it is then monitor the temperature on the thermostat housing using a laser temperature gauge and see if the temperature is actually doing this.

https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

https://www.2carpros.com/articles/how-to-use-an-infrared-temperature-meter

If it is then you have a thermostat that is opening and closing which means you need to remove it and put it in a pot of water and boil it and see if it is opening properly and staying open.

I attached the info below as I suspect this is a sensor issue. Please let us know if you have other questions and what you find. Thanks