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
yeah this happens in my career also, but not to me, the AI seems to be having issues with this, particulary Max Verstappen. In driver career mode I added Konnersport and Max Verstappen switched from Red Bull to Konnersport for 2nd season and both in Imola and Monaco (2 races in a row) he was just sitting there in the pitstop waiting for a green light while there was nobody around him
Link: AI stuck during pit stop