X15 Random Coolant Loss

[BobbyTTour]

We have a 2019 X15 with 330,000 miles that is randomly consuming coolant. It consumes 1-2 gallons after the driver stops for his 30 min break after driving for a few hours. He will check it when he stops and it may be down about .25-.5 galleons, and within driving 20 miles after the break, he gets the low coolant warning and has to add 1-2 gallons. It will then be fine the rest of the day and might be down .25-.5 gallons at the end of the day. This has happened for two days in a row. He stopped at a shop and they performed a pressure test and said they couldn’t find it and suggested we replace the injector cups. I was thinking it was and EGR cooler issue. Thoughts?

Thank you.

Robert