4th gear problem with kia c"eed SW

bought a kia ceed sports wagon two weeks ago brand new, no miles. when i put car inot 4th year it shakes for two or three seconds then is fine. havent contacted dealer yet as i was wondering if it was just the car "settling in ". any ideas ? time to bring it back for a check?

definetly bring it back,, gearboxs dont 'settle in'

okay cheers, wouldnt have a clue about cars myself!