EDIT: This problem is fixed in the post-PAX build
On attack, 2nd objective, I respawned a second or two before our C4 blew up the train car. So I got off the tracks, watched the train go by and proceeded to follow it. As I got to the decon area (the giant car wash), the door the train went through was opened but I still couldn’t pass:
I went around the right and then tried to enter the decon area through the opposite door (which the train had ran through as well), same invisible wall:
