You stand still for up to five seconds, even though there are no vehicles nearby, until clearance is given. Gaps between vehicles are ignored, even though 10 vehicles could fit between them.
Ideas
Happened in multiple races with my teammate in My Team Career mode, both in dry and wet conditions and pitting during safety car deployment. The pit crew finished changing tires with no errors, and the car gets held up for absolutely no reason at all while other cars in the pit lane pass by. Lost multiple places to go from P2 to P16. Pit Release Assist is off for the player (me)