Workaround for a seemingly platform specific artifact (tile shaped artifacts) when both Substrate and r.Shadow.StencilCulling are enabled. The workaround forces a dummy pixel shader with late-Z in the stencil masking pass, which seems to fix the bug.
Usage
r.Shadow.StencilCullingArtifactWorkaround [value]
Set via the console (~) or in DefaultEngine.ini / DefaultGame.ini.