This is the plane I created. It is correct with the right orientation.
After I press the E extrude the hotkey. It generates another orientation. It is fine if I just pull it up and make a cube.
But I want to make it bigger, so I press S to scale it up. Now the problem starts to show up.
The middle one generates 2 orientations. I tried to merge the vertices to fix the problem. But it doesn't work.
neither Recalculate normals work
Is there anyone encountered the same problem and solved it?