This has been fixed in 5.8, but if you’re stuck on 5.7 you can manually patch in the fix as it’s just a buildin shader that needs fixin.
So in \UE_5.7\Engine\Shaders\Private\StochasticLighting\StochasticLightingTileClassification.usf
On line 636 (if in Vanilla) add if (bIsAnyValid)
Then just restart your engine, or execute the console command
RecompileShaders changed, and it’ll be fixed.