If the car sits for at least 2hrs, it will smoke (blue) for a few seconds after startup and then the smoke completly disapears. What is the cause? Is it normal? And will it lead to futture problems?

Either turbos or oil control rings come to mind....or a combination. Did you get that limp mode issue resolved? Because usually if it's the turbos, I think you'd see more smoke at WOT.

Future problems? It's not gonna heal itself, but as long as it burns off quickly, it won't harm anything except maybe plugs over time. I guess if it got really bad it could also plug your cat prematurely.

Things will only get worse thats for sure. Chances are its your turbos on their way out. Pull your spark plugs and see if there is burnt oil on them. Pull your intercooler piping while your at it and see if they are oily..