In these images I have explained the matter to you and others who might find this problem: The symbols in im1 are not in their own corresponding quarter. Why? because they have rotated and I told you the reason why. In the second image (im2), by applying a proper initial phase to the laser, they are rotated back, well, not exactly to their own place but at least to their corresponding quarter and that makes the detection correct in this example. Just so as you know, I applied initial phase=-145 in this case (and you can see this by comparing the images). I hope I made it clear to you now.