I’m having the exact same issue in 4.13 as Luke has described very detailed DFAO making everything look extremely reflective - Rendering - Epic Developer Community Forums
It requires several steps to reproduce the issue, I have created a example Project Just Load up the Starter Map and take a look into the “house”. If you disable/toggle the visibility of the sphere reflection capture you should clearly see the issue. File-Upload.net - Datei nicht gefunden
The most crucial steps are to enable DFAO and disable lower hermisphere is black. It is predominantly visible in indoor scenes.