Just came across this bug, first play of the preorder demo.
I had double-clicked one unit past the door from 10 units away and ended up stuck outside in the doorway unable to move. Also had the looping footstep sound (continuing through Hidden Movement, etc.)
I was able to "escape" by right-clicking on my next turn, it may have been to one of his sides or just in front of him, I'm still not quite sure exactly how it happened. Either way, the sound stopped looping and I was FREE! I guess since right-clicking is to just open a door and not walk through it, the action may have caused the game to believe the door was now open (even though it already was) and free of obstructions.