The shaders flicker when in Lightmap Density viewmode after enabling Instanced Stereo Rendering in Project Settings > Engine > Rendering > VR
Tested in 4.21.2 (CL - 4753647) 4.22.3 (CL - 7053647), 4.23 P6 (CL - 7948402), 4.24 (CL - 8122865)
Expected: The view mode would show how the light is affecting the meshes in the scene
Result: The view mode has black triangles that flicker upon movement in the scene
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-79151 in the post.