I've observed this issue in 4.18.3 and 4.19.1.
So we've spotted an issue that I wanted to put on your radar with dynamic shadowed stationary lights + r.ForwardShading=1
What we're seeing is no dynamic shadows of any kind (no dynamic inset, no CSM etc) being cast from stationary directional lights, until we've done a lighting build. Things to note here:
- This only appears to be happening in forward shading
- We are seeing in-editor preview shadows, it's just in PIE or built games that we're not seeing dynamic shadowing from 'unbuilt' stationary lights.
- After building lighting; CSM, dynamic inset shadows etc then show up in PIE as expected.
- After building lighting and having everything working, then rotating the light seems to invalidate it again and we go back to no dynamic shadows until we rebuild.
Of course we can simply build lighting to get the shadows we're after (this seems to be a persisted state btw, saving the level after building lighting seems to work as expected)
Result: Shadows are visible in Editor viewport, but not when PIE.
Expected: Dynamic shadows visible
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-58189 in the post.