Yes more than likely the dpf is partially blocked. Car has to regenerate the dpf to clean it out. One of the ways it does this is that it overfuels at certain times to ignite the excess fuel in the dpf. This cleans it out as the temps go over 800 Celsius. If the dpf is too blocked to regenerate the excess fuel will be forced past the usually the piston rings and "tops" up the oil level.

How to fix it. Change the oil and filter as now it has some diesel in it. Then drive the car hard up the motorway at a constant speed of about 70-80kmh.

If it happens again then you need to see a) if the dpf is blocked and b) why it's blocked.