When enabling Forward Shading in a project while using the Lumen Global Illumination system, the shadows in the viewport begin to flicker and occassionally entire meshes may appear black. The lighting also seems overblown as well.

I tested this with Forward Shading disabled and did not encounter the issue. I also tested with Forward Shading enabled, but Lumen disabled and did not encounter the issue either, so it seems to be the combination of both rendering settings.

Steps to Reproduce
  1. Open any project in UE5
  2. Navigate to Edit > Project Settings
  3. Under Engine > Rendering, tick the box next to Forward Shading
  4. Restart the engine


The shadows start to flicker


Forward Shading would not causing Flickering when using the Lumen GI system

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ComponentUE - Graphics Features
Affects Versions5.0-early access
Target Fix5.0
Fix Commit16775519
CreatedMay 26, 2021
ResolvedJun 24, 2021
UpdatedSep 19, 2021