I have a post processing volume added on my scene, but as you see the grass doesn’t propperly render the shadows unless they’re fully behind a landscape shadow, does someone know any way to solve this issue?
What shadow type are you using?
classic foliage shadow issue: Landscape grass type (procedural instanced) uses Camera Shadow Pass trick that breaks at close angle unless RVT / landscape is contributing correctly.
try set LandscapeGrassType Overlay Material RegisterWorldHeightMap, bump r.shadow.CSM.MaxMobileCartoonsResolution or set Close/Shadows range on DirectionalLight. also enable r.Foliage.Shadows 1, and make sure your grass meshes are Nanite, they barely shadow otherwise without Virtual Shadow Maps (its on by default in newer versions).
in post process volume check Cast Shadow Mountains enabled and you arent forcing Lumen off.