The problem comes from how the program was created. There is are rendering issues with using Godot Forward+ and mobile as the base of making a Godot program. It affects computers that are 1-2 years old and have a high end graphics card. I have this issue with multiple Godot Desktop pets. He would need to change the renderer to compatibility mode to remove the black box.
https://forum.godotengine.org/t/transparent-background-show-black/52877