Hello, got a 2003 X5 3.0i auto

Ive noticed if the car isn't driven for few days, that when you get in it to drive away, engage drive, the car barely moves forward even though the revs go high (3000 to 4000 rpm)
Then it feels like it kicks properly in to gear and is absolutely fine after this with no clutch slip whatsoever.

Has anyone experienced this or know whats going on?

Thankyou