Draw a line with Niagara System: ugly effect

Hi!

I’m trying to draw a line with Niagara System using Unreal 5.2.1, and I did it, but with a side effect:

imagen

That kind of triangle changes, it goes brighter and then, less brighter, and then brighter…

By the way, I use an emissive colour.

I don’t know how to share with you the Niagara effect, only this screenshot.

Do you know how I can avoid it?

Thanks!