Problem while using Depth Buffer (Depth Mask) in Unity

While using some 3D models the depth Mask Shader which is having z-test as "LEqual" need to perform normally as in [screenshot1]

but it give result which shows grayscale outlined of that part of 3d model where it need to be hidden. [Take reference of screenshot2]

Here is the Custom Shader file data

Shader "Custom/mask" { SubShader { Tags { "Queue" = "Geometry+10" "RenderType" = "Opaque" }

Lighting Off ZTest LEqual Cull Back ZWrite On ColorMask 0 Blend One One Pass {Fog {Mode Off}}

} }

We have tried changing the ZTest from LEqual to Always which solves the problem a bit but again the object is partially visible.