Coolant Temperature Fluctuations

What is your question?

3 days ago while driving, my coolant level spiked to 250+ degrees randomly. I pulled over and looked at everything and my reservoir was empty. I filled my reservoir however nothing changed with the temperature. I brought it to a mechanic and initially it wouldn’t keep pressure and they believed a hose was broken. They bled the entire system, flushed it, and ran a pressure test and it was fine. Nothing was fixed. The jeep was then driven 200+ miles without any issue. Today, again, the temperature randomly spiked to 250. Letting it sit for about 5 minutes allowed it to regulate. Then for about 10 miles it was changing from 211-245. I’m assuming the thermostat is sticking. Do you agree?

How long has your 2018 Jeep Wrangler had this problem?

A few days