I am amazed how in US closing elevator doors switch to opening if someone touches the door edge. This results in abusive behavior of people intentionally jamming their arms in the path of closing doors, and delaying everyone else inside the stopped elevator.
I like to think I'm reasonably well-traveled, and I've never seen an elevator NOT do that.
However, I think you might be correct about transit systems, where the blocked doors might re-open a small amount before quickly attempting to re-close, to keep the train on schedule and prevent this behavior.
The alternative being closing the doors on the person's arm and likely injuring them to avoid a minor incovenience?
That's the case with most elevator doors, worldwide...? If you put your hand in a closing elevator door, it's supposed to open again.