A sprite2D still interacts with lights even when alpha is set to zero

Help
,
1

Godot Version

4.5.1

Question

I have a problem with a 2D scene where i would like to have a fading animation for a sprite.
The main components of the scene are:

  1. 3 Point Lights, with blending mode set to “add”
  2. A directional light, with blending mode set to “mix”
  3. No global enviroment node
  4. The sprite has the standard default material

The sprite has a modulate property set to Color(2.007, 1.248, 1.501, 1) (purple like) or if you prefer the classical RGB(255, 156, 189, 255) with Intensity +2.32. It is an HDR color
The fade animation simply change the modulate color linearly to Color(1,0.61,074,0) so the final color is not HDR and fully transparent.
The animation works, in the sense that the sprite becomes “transparent” however somehow the lights still interact with the sprite because there is a “purplish” halo where the sprite is suppose to be.

I have no idea how to remove it.
I could use visible = false/true but this is an on/off switch and i would prefer a gradual effect.
Can anyone help me explaining what is going on?

2

Reduce the problem to a single light.

Post some screenshots.

What happens if you just manually set modulate alpha to zero?