Raymarching Bug - Rendering 3D texture in real-time

I am working on a project for a client and I am trying to replicate the 3D volume rendering done in the Unity Inspector so I can view changes to 3D volume data in real-time.

Here is an example of what the final output should look like (with and without transparency):

https://imgur.com/a/unboPgk

However, when I render this in real-time using a slightly modified version of the default Raymarching shader provided by Unity - my results are quite different.

https://imgur.com/a/fNMguu4

Here is the shader code being used to render the 3D texture:

 Shader "Unlit/3DVolumeShader"
 {
     Properties
     {
         _Alpha ("Alpha", float) = 0.8
         _StepSize ("Step Size", float) = 0.01
     }
     SubShader
     {
         Tags { "Queue" = "Transparent" "RenderType" = "Transparent" }
         Blend One OneMinusSrcAlpha
         LOD 100
 
         Pass
         {
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
 
             #include "UnityCG.cginc"
 
             #define TEX_WIDTH 512
             #define TEX_HEIGHT 64
             #define TEX_LENGTH 384
 
             // Maximum amount of raymarching samples
             #define MAX_STEP_COUNT 128
 
             // Allowed floating point inaccuracy for hit detection
             #define EPSILON 0.00001f
 
             struct appdata
             {
                 float4 vertex : POSITION;
             };
 
             struct v2f
             {
                 float4 vertex : SV_POSITION;
                 float3 objectVertex : TEXCOORD0;
                 float3 vectorToSurface : TEXCOORD1;
             };
 
             float _Alpha;
             float _StepSize;
 
             StructuredBuffer<float4> DensityMap;
             
             v2f vert (appdata v)
             {
                 v2f o;
 
                 // Vertex in object space this will be the starting point of raymarching
                 o.objectVertex = v.vertex;
 
                 // Convert vertex in object space to camera coordinates
                 o.vertex = UnityObjectToClipPos(v.vertex);
 
                 // Calculate vector from camera to vertex in world space
                 float3 worldVertex = mul(unity_ObjectToWorld, v.vertex).xyz;
                 o.vectorToSurface = worldVertex - _WorldSpaceCameraPos;
 
                 return o;
             }
 
             // This method blends colors based on their alpha transparency
             // If color.a == 1 then no blending will occur
             // Otherwise multiply the difference in the alpha's by the new color
             float4 BlendColors(float4 color, float4 newColor)
             {
                 color.rgb += (1.0 - color.a) * newColor.a * newColor.rgb;
                 color.a += (1.0 - color.a) * newColor.a;
                 return color;
             }
 
             fixed4 frag(v2f i) : SV_Target
             {
                 // Start raymarching at the front surface of the object
                 float3 rayOrigin = i.objectVertex;
 
                 // Use vector from camera to object surface to get the ray direction
                 float3 rayDirection = mul(unity_WorldToObject, float4(normalize(i.vectorToSurface), 1));
 
                 float4 color = float4(0, 0, 0, 0);
 
                 float3 bounds = float3(TEX_WIDTH, TEX_LENGTH, TEX_HEIGHT);
                 float3 samplePosition = rayOrigin;
 
                 // Raymarch through object space
                 for (int i = 0; i < MAX_STEP_COUNT; i++)
                 {
                     // Accumulate color only within unit cube bounds
                     if(max(abs(samplePosition.x), max(abs(samplePosition.y), abs(samplePosition.z))) < 0.5f + EPSILON)
                     {
                         // Sample the color at the position in our density map. Add an offset for UV coordinate transformation.
                         // float4 sampledColor = tex3D(_DensityMap, samplePosition + float3(0.5f, 0.5f, 0.5f));
 
                         float3 textureCoord = (samplePosition + float3(0.5f, 0.5f, 0.5f)) * bounds;
                         int index = int(textureCoord.x) + (int(textureCoord.y) * bounds.x) + (int(textureCoord.z) * bounds.x * bounds.y);
 
                         float4 sampledColor = DensityMap[index];
                         sampledColor.a *= _Alpha;
 
                         // Blend the colors based on alpha transparency
                         color = BlendColors(color, sampledColor);
 
                         samplePosition += rayDirection * _StepSize;
                     }
                 }
 
                 return color;
             }
             ENDCG
         }
     }
 }

I am using raymarching to index into the 3D texture array, which is where I think this issue might be occurring. I'm wondering if I might have something wrong with the scaling/coordinate system that Unity uses.

My texture size is 512x64x384 and I am rendering to a cube with scaling 1x0.1x0.75.

Please let me know if there is any additional information required to solve this.