Left/Right automatic pushback uses data from the scenery and tries to reach certain nodes. Nothing ensures it's possible to end up on a certain node and follow the ground lines, especially in such a cramped position. In fact, considering that position, GSX made a remarkable job doing a reasonable automatic pushback.
Which is why, there's a Custom pushback option (either pre-made or when using QuickEdit), where you can have a far greater control over the path taken, by acting on the positioning AND heading of the controlling waypoints.