This is a rather tentative idea, but if it does this after starting in the morning it may just be that your battery is not charging as well as it should; possibly its getting on a bit or hates the cold. The engine is trying to charge the battery asap, and thus doing this off its own bat, as it were.
Not that a new battery is a cheap option - i have just forked out £65.00 for one!
My RR used to do this, but a change of battery has cheered it up a lot, and it is behaving a lot better in the mornings.