Seeing the image, Mike, my first thought was wow, I love that font! It took me another second to realize it was familiar. ;) I doubt this is a bug as such, but perhaps an oversight. Maybe when they were building the Glow element, they didn't consider maybe there would be a mirror around. But I agree, it should reflect...not just for a mirror, but also in water, or glass, etc. I had the same problem in v.3 with certain point lights not reflecting. Haven't had a chance to recheck them with v.4 yet.