Why is this point light square?

Hey all,

I was writing a shader and thought everything was going great until I added a point light over a larger piece of geometry and noticed that point lights were appearing squared if the geometry didn't fully fit within the range of the light. I was reading that this had to do with the attenuation. However, nothing changes no matter what I do with the attenuation. I've noticed that Unity's default shaders do not do this. Here's an example of the problem:

I decided to take a step back and try to see if I could get this working on a simpler shader. The lighting is being done on the vertex level. The shader code is below.

 Shader "Custom/FromScratch" {
 
     Properties {
         _Color ("Color", Color) = (1.0, 1.0, 1.0, 1.0)
     }
     
     SubShader {
         
         Pass{
             Tags {"LightMode" = "ForwardBase"}
             
             CGPROGRAM
             
             #pragma vertex vert
             #pragma fragment frag
             
             //user defined
             uniform float4 _Color;
             
             //Unity Defined
             uniform float4 _LightColor0;
             
             struct vertexInput{
                 float4 vertex: POSITION;
                 float3 normal: NORMAL;
             };
             
             struct vertexOutput{
                 float4 pos: SV_POSITION;
                 float4 light : TEXCOORD0;
             };
             
             
             vertexOutput vert(vertexInput v){
                 vertexOutput o;
                 
                 float4 posWorld = mul(_Object2World, v.vertex);
                 
                 float atten;
                 float3 lightDirection;
                 
                 float3 normalDir = normalize(mul(float4(v.normal,1.0), _World2Object).xyz);
                 
                 //lighting
                 if(_WorldSpaceLightPos0.w == 0.0){
                     atten = 1.0;
                     lightDirection = normalize(_WorldSpaceLightPos0.xyz);
                 
                 } else {
                     float3 fragmentToLightSource = _WorldSpaceLightPos0.xyz - posWorld.xyz;
                     float distance = length(fragmentToLightSource);
                     atten = 1 / (distance * distance);
                     lightDirection = normalize(fragmentToLightSource);
                 }
                 
                 
                 float3 diffuseReflection = atten * _LightColor0.xyz * max(0.0, dot(normalDir, lightDirection));
                 o.light = float4(diffuseReflection.rgb, 1.0);
                 o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                 
                 return o;
             }
             
             float4 frag(vertexOutput i):COLOR{
                 return i.light;
             }
             
             
             ENDCG
         }
         
         Pass{
             Tags {"LightMode" = "ForwardAdd"}
             Blend One One
             
             CGPROGRAM
             
             #pragma vertex vert
             #pragma fragment frag
             
             //user defined
             uniform float4 _Color;
             
             //Unity Defined
             uniform float4 _LightColor0;
             
             struct vertexInput{
                 float4 vertex: POSITION;
                 float3 normal: NORMAL;
             };
             
             struct vertexOutput{
                 float4 pos: SV_POSITION;
                 float4 light : TEXCOORD0;
             };
             
             
             vertexOutput vert(vertexInput v){
                 vertexOutput o;
                 
                 float4 posWorld = mul(_Object2World, v.vertex);
                 
                 float atten;
                 float3 lightDirection;
                 
                 float3 normalDir = normalize(mul(float4(v.normal,1.0), _World2Object).xyz);
                 
                 //lighting
                 if(_WorldSpaceLightPos0.w == 0.0){
                     atten = 1.0;
                     lightDirection = normalize(_WorldSpaceLightPos0.xyz);
                 
                 } else {
                     float3 fragmentToLightSource = _WorldSpaceLightPos0.xyz - posWorld.xyz;
                     float distance = length(fragmentToLightSource);
                     atten = 1 / (distance * distance);
                     lightDirection = normalize(fragmentToLightSource);
                 }
                 
                 
                 float3 diffuseReflection = atten * _LightColor0.xyz * max(0.0, dot(normalDir, lightDirection));
                 o.light = float4(diffuseReflection.rgb, 1.0);
                 o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                 
                 return o;
             }
             
             float4 frag(vertexOutput i):COLOR{
                 return i.light;
             }
             
             
             ENDCG
         }
         
         
         
     }
     FallBack "Diffuse"
 }
 

Is there anything I can do to make sure the light falls off before the light's range? Or should I just set the range to a crazy high value? Thanks for any help!