Hey there. So for some reason, when I spawn in a decal, and change the material, its a plain tile. Restart, doesn’t work. Even when I build the lighting, Its the same tile texture.
I really need help or I’ll have this decal problem forever. Thanks!
I’m having the same issue. Did you solve your problem? 
I had the same issue, but I figured it out:
The material that you want to be the one on the decal has to be set as a ‘Deferred decal’ as Material Domain in the settings of the material itself