As you can see in the attached photo, when I adjust the transparency on an object, half of it looks weird.
Have you ever seen a case like this?
It happens even when I control both the depthTest and depthWrite properties of the material.
If I open that gltf file in blender, it looks weird, and if I turn off Show Backface, the transparency works fine.
But when you view it in threejs, the transparency looks weird.