Shadows Turning Black and Unwanted Shine on Terrain in Unity URP

Hello, I hope you don’t mind me asking for help, as I am a beginner and facing an issue I don’t understand despite spending several hours searching and trying various solutions. I have a Terrain where I want to apply textures (Layers) to add effects like grass, mud, etc. However, as soon as I create the Terrain, the shadows turn black, and it has an unwanted shine (image). I noticed this happens because of the Universal Render Pipeline > Terrain > Lit material. When I use a “normal” texture, the shadows and shine look fine. Do you know how to fix this issue?

Hello, I tried starting fresh today by following a tutorial. I created a new 3D Mobile project, installed URP, and configured new Universal Render Pipeline Assets. However, I’m still facing the same issue: as soon as I apply a Layer to my terrain, I get this reflection/shine effect. (Even though I don’t have any other settings that could be causing this problem.)

I also tried creating a custom Shader to apply to the terrain, and while it works, I can no longer paint my terrain as I want because the Shader is not set to Universal Render Pipeline/Terrain/Lit.

Do you have a solution or a tutorial that I might have missed? Thank you so much, I’m hoping for a generous soul to shed some light on this!