When I first retired from the military I was a maintenance manager for Caterpillar and then Detroit Diesel, EGR valves on diesel engines are high failure parts. Darned if I know why, but we would put one into a vehicle and 3 weeks later the darn things would fail. We even had some fail on trucks still sitting at the dealership never even delivered yet. Sad when you can't trust a newly manufactured part to make it 50 miles.
I will personally never own a modern diesel. The old ones were pretty darn reliable, the news ones, not so much.
OK, error code unknown on my vehicle, but was told a egr code that was the root cause for start/stop issue. Hate that start/stop function, hate it worse that stuff ain't working correctly.