Strange Shadow Ghosting in preview windows when viewport set to show lit scene

Development Rendering
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1

I’m reporting a potential bug and if not asking a question about how to solve this strange problem I’m facing. Using UE 5.4 and 5.5 on Windows 10 22H2 and an RTX 4090 with driver 566.32, when the viewport is set to Lit there is strange ghosting showing up in the shadows and when panning textures across a material.

Here’s an example, in the Blendspace animation preview window using the Third person template and blending between the walk and run default animations. See the artefacts on the shadow in the bottom right.

Here’s an example of the panning issue on a simple animated material (taken from the Unreal Fellowship 2024 materials exercise):

I found that disabling antialiasing under Show seems to remove the issue but I’m concerned this is hiding a deeper problem for shadows:


Switching to unlit also seems to not show this ghosting when panning materials:

This looks like some sort of bug as I don’t remember seeing this on 5.2 blend spaces but if anyone could confirm or suggest if there’s a configuration issue that might help resolve this it would be very helpful.

2

I’m posting findings here in case this helps anyone:

  1. This problem may be caused by nvidia driver versions but unclear and with the current state of nvidia drivers, the one I’m using would be the most stable
  2. Switching the desktop renderer anti-aliasing method from the default TSR to FXAA eliminates this strange shadow ghosting problem but FXAA introduces some occasional shimmering at some angles
  3. Trying to use Lumen/ray tracing doesn’t fix the issue
  4. Using DLSS/DLAA eliminates the shadow problem but can introduce artifacts in images (as expected with any non-raster renderer)
  5. Increasing engine scalability settings from epic to cinematic doesn’t fix the problem

At this point, there simply doesn’t seem to be a solution other than potentially playing with drivers which would be uncertain. If anyone has any insights/actual fixes, please contribute.