Re: Interesting justification.
Idling to warm up a car is discouraged in Germany (due to the fumes and emissions), and is illegal when stopped at railroad crossings. It could well be that the lean mix is intended for short idles (or perhaps discreet warm-ups on winter mornings).
There are now start-stop motor control systems, but they require a sturdier battery and charging system (particularly in winter) and do take a mechanical toll on the engine, depending on how long it's stopped, etc.
Considering that Bosch makes a lot of the injection hardware and controllers, I wouldn't be surprised if there were a lot more companies that might get caught out. There are test organizations in Germany looking at just that.
Also, the standards that "aren't being met" are close to impossible to meet, and although recently approved by the idiots in Brussels (who usually don't have a technical clue), are still the object of heated (sorry) discussion amongst engineers. Pi$$ in the tank, aka AdBlue, is not the friendliest or most economical solution, but so far it's just about the only one.
Seems like someone wants to kill diesels off - the US never has liked diesel cars. Wonder if Tesla's overstating its horsepower will get as much attention?