You can see two audiostreamplay nodes with different property why this happened? I try to make the two nodes load the same audio file(at this time two nodes means already completely same to me except the name of node), but not change the property.
One is an AudioStreamPlayer, the other is an AudioStreamPlayer2D.
Those are two different classes. AudioStreamPlayer is for background music. AudioStreamPlayer 2D is positional sound, so used for sound effects (like a voice will come from the left or right side depending on where the character is).