Changing Vector Parameter in Additive Material via BP causes strange results

Hey guys,

I need help. I have a lamp blueprint, which consists of a mesh, two shapeplanes that imitate lensflares and a spotlight. For some reason the light color of my lensflares does not match the color of the spotlight, even though they both receive the same color channel. Why does this happen? How can I fix it? The same thing happens when I use a point light. You can see the screenshots of my code below.

There are no post process fx used on the attached scene and there is no color overlap from another light or fog. The aura of the light in the attached image is a fake lens flare created by two shape planes. These shape planes have a lens flare material (additive), which contains a vector parameter connected to a multiply node which in turn multiplies the vector parameter with the original lens flare texture. This vector determines the color of these lens flares. Everything looks and works fine until I start the game. The blueprint is supposed to assign the same random color to the spotlight and these shape planes. But for some reason the colors of both components do not match, even though they receive the same color values in the blueprint on BeginPlay. In the image the spotlight color is white, but the lens flare color is purple. I cannot figure out why this happens. Both should be either white or purple, but not two different colors. This happens across the board on every instance of this blueprint in various color combinations every time I start the game.

Any advice is greatly appreciated, because I’m at a loss.