I’ve created a decal material that correctly renders on a Default Lit material. However, it does not render on an Unlit material. I can’t think of a reason why this wouldn’t work, so I’m guessing it’s a bug. All of my materials are unlit in my stylized game, and it seems brutal that I can’t use decals at all.
Basically just the steps that the OP mentioned in the original report. If you still aren’t able to get this working, feel free to post screenshots and a description of your setup.