I've noticed on London Commuter that the doors keep automatically reopening after they've been fully closed. They do this more than once at a time and lead to colossal delays. This bug seriously stands out and is in need of addressing.
I've generally found a way to reproduce this problem, by taking over a Service when the AI Train is already loading Passengers. You cannot close the Doors until the exact Departure Time otherwise they just continuously keep re-opening. Once you reach the next Station, the second you stop, the Doors will automatically open. Can't say I've had this happen with a Service I have started from scratch though.
Had this several times across a few DLC, it's like an AI guard is controlling the doors for you, immersive wise it's great, but does occurs delays as you go