Decals disappear when I rebuild lighting

I am trying to get some realistic looking blood spatter on the walls and floors of my level using decals. When I bring them into the level, they look like this:
This is how I would like them to appear in game. However, as soon as I rebuild the lighting, they look like this: 07934b177532a7c8a0bc38cacb028b5579bcb6ee.jpeg
This is the material set up:

Any idea what is causing the decals to fade and/or how to fix it so that they show up vibrant?