Unreal light artifact with roughtness

Hi!

Are you using Lumen for this lighting? If so, you might want to check the scale of your project and make sure it’s not too big. Also make sure that your graphics quality is set to at least High. You could also try increasing your Lumen samples.

Here is a forum thread about a similar problem:

And here is an article that may help:
https://dev.epicgames.com/documentation/en-us/unreal-engine/lumen-global-illumination-and-reflections-in-unreal-engine?application_version=5.2