Morning Paul
Welcome to the Forum
Nice car.
All modern cars but diesels in particular are not happy with short journey's where they don't reach full operating temperature. Exhaust temperature is the most important to allow the Emissions equipment and DPF to work correctly. Your car is under warranty so you have a few years protection but time spent at the Dealer is frustrating.
Our youngest son (mid 30's) runs a diesel Toyota Pickup) 80% of his journeys are local and he was getting issues until he learned that at least once a week the car needs a good blast at least 50 miles at good speed to make sure the emissions stuff gets to working temperature and can do it's job. All was good for the first 2 years then the EGR system needed attention frequently .he is a tree surgeon so while the Toyota Garage were great and always offered a courtesy car it couldn't carry all his kit? He was on the verge of getting rid when one of his customers with a commercial diesel business (Truck Service) told him to give it a good "Italian Tune Up" once a week. In his 3rd year ownership we would remove and clean the EGR monthly, the real issue was the DPF wasn't getting hot enough to regenerate and burn of the soot. Since he changed his driving habit we have only cleaned the EGR once in 2 years.
So my advice,from what I have learned and since read is at least a couple of times a month give it a good blast to let it clear it's throat.
Enjoy your Beemer
Dave