Problem with MeshPhysicalMaterial : Black artifact?

Hi, i’ve just started playing around with threeJS and stumbled upon something i can’t seem to resolve on my own.
I made a pong game and was trying to make it look a little better so i gave a go to meshPhysicalMaterial and tried to give my paddles a glass look.
But here’s the problem. Sometime the glass seems to reflect / or show by transparency a sort of black object that is not present in my scene. (If it can help I’ll try to upload a gif)
I tried changing the way i implemented the skybox, i tried another way of giving the paddles a glass effect and changing the rendering order but nothing worked so far.

Capture d’écran 2024-01-27 à 16.58.05

Here is the paddle code (The movement is irrelevant i just update the y position received from the server)

	var g_paddle1 = new THREE.BoxGeometry(0.2, 2., 2.);
	var g_paddle2 = new THREE.BoxGeometry(0.2, 2., 2.);
	var m_paddle1 = 	new THREE.MeshPhysicalMaterial({
		reflectivity : 0.3,
		transmission : 1.0,
		roughness : 0.8,
		clearcoat : 0.3,
		clearcoatRoughness : 0.25,
		ior : 1.2,
		thickness : 10.0,
		side : THREE.BackSide,
		color : new THREE.Color(0xff0000),
	});
	paddle1 = new THREE.Mesh(g_paddle1, m_paddle1);
	paddle1.position.x -= 5;
	paddle1.rotation.x = Math.PI / 180 * 90;
	paddle1.renderOrder = 2;

Just fixed it. After some test and trying to find where it was coming from, i found out that it was in fact the scene background that was not set. I don’t really know why it wasn’t working before but if it can help somebody else here it is.