It's not really the fact it shuts off or doesn't shut off but rather that it does it sometimes and other times it does not. I believe it should do it all the time or not do it all the time.
RTFM. The owner's manual specifically states that it will do it sometimes and other times not.
You are experiencing that very scenario, yet you are denying--despite the now revealed actual documentation--that it should ever happen that way.
again: what makes you say that the behavior you initially observed is the "right" behavior and that today's behavior is the "wrong" behavior? Is it simply that "initially it always did it, but now it doesn't always do it"?
And, considering I'm in Race/Sport mode all the time, start/stop should be deactivated and the engine should not shut off until I press the Start/Stop button (or during the quoted manual section above) but it does (sometimes) when simply moving the shift lever to Park.
Per the documentation that we see, that is correct--it should not shut off at all in race/sport mode. I can see three considerations:
* the manual is wrong
* your car is broken/not functioning to spec
* you're not in race/sport mode despite you thinking you are
As an engineer, you should appreciate that you can control for the third item above and test for it very carefully.
So, to me, this is inconsistent, poorly documented, and definitely not intuitive.
The manual should have already clued you in that the start/stop behavior is programmed to behave in ways you consider "inconsistent"--for example, you don't have direct knowledge of the charge state of the battery therefore you wouldn't know what effect that has on the system's decision to turn the engine off or not.
If the system is behaving as the engineers intended, it surely is poorly documented at best. But at least the documentation does clue you in that at least some behavior you consider "inconsistent" is actually programmatically correct.
And of course, there's the "it's broken" thing.
I can see the lawyers programming in the behavior of "if start/stop has the engine stopped, AND the car is in Park, AND the seatbelt is unbuckled, AND the door is opened--then turn the system off" in order to avoid the inevitable lawsuits from people like those who leave their cars "on" in their attached garages and got CO poisoning or death, all because they didn't understand keyless start and start/stop.