There are no regressions to the ATC_parking_type or taxiwayparking, planes that do spawn still follow its cargo/gate restriction as well as wingspan radius.
This behaviour happens with simconnect however I am unable to test with the default-AI as those don’t have airlinecodes; Custom FS2020 BGL-AI traffic is also unimplemented in this build as I have reported over in this thread and therefore I cannot test with BGL spawning.
From further testing it seems like there is some sort of blocker limiting AI planes from spawning at airports. As soon as AI-traffic aircraft pushes back another aircraft spawns immediately at the gate it departed at. I have also tried force-spawning AI through simconnect which also fails to spawn additional planes when there are still gates available.
As a result, it is probable that AI is not following airlinecodes because there is a potential limiter or bug where AI is restricted to park at certain gates. Aircraft are then forced only to spawn at those certain gates. Do keep in mind that these packages have not changed from FS2020 and all AI airplanes continue to spawn properly in FS2020.