This has been discussed so many times on the forum and no, it doesn't have anything to do with the update.
In order to see passengers, and to have them boarding/deboarding with realistic times, the scenery must have either:
- A least one GSX/SODE jetway that has been docked.
OR
- A SODE jetway provided by the scenery that has been docked
OR
- If the parking is not a gate with a jetway, stairs and a passenger bus must come
If none of these conditions are valid, boarding/deboarding of passengers will be simulated like in the basic GSX, and will run much faster.