2014 Ford Mondeo rough start on a diesel automatic

So this is a problem that I have had now happening twice (in about 6 months), but it does raises my concern. I got a Ford Mondeo Diesel Mk4 with a Powershift automatic gearbox (which was replaced with a new one following a pesky clutch problem), and when we turned the key, it started -and ran very rough. Turned it off immediately, and tried again, but this time it started fine.

Curiously, both of these two occasions happened when someone else drove/started my car (I think my Mondeo doesnt like to be driven by other people). I wonder whether this is something to do with how you turn the key, aka, how long do you keep it in the "fiering" position. I did notice that other people turn it into the "fiering" position and then immediately let go; while I usually "keep" it "fiering" for about a second to make sure the engine is running before letting go (still used to the old diesels).

Obviously, when I tried to demonstrate this with a mechanic the car worked fine (typical) so he couldnt comment on this. Does anyone else have this problem? Is this something documented?