Niagara Particle Sprites turns black when looked against the light

Hi everyone, I’ve done a simple Niagara Emitter for some smoke.

The sprites are facing the camera, the texture is an atlas and it uses subuv.
When I put the System into the level, even in the editor ( not only in play ) anytime I turn to look them against the light, the color of the smoke turns black. The alpha still remain good though.
I can really see as I move the view the smoke turning from his original color to black.

In my scene there is a SkySphere with a DirectionalLight. The project doesn’t use raytracing.
I just can’t find a way to make it work. The project is made in 4.26.2

Thank you in advance!