A little help with pixel position calculation

Hello everyone, I'm building an app that uses a depth camera to send a point cloud over the network to a client that has to visualize it. Everything works fine on the server but on client all the points that represent negative coordinates respect to the pivot (0, 0, 0) a aren't visible. I use the same shader in both apps and on the server side there is no problem. This is the shader:

Code (CSharp):

1. Shader "PointCloud"
2. {
3.     Properties
4.     {
5.         _MainTex ("Texture", 2D) = "white" {}
6.         _Size("Size", Range(0.1,2)) = 0.1
7.     }
8.     SubShader
9.     {
10.  
11.  
12.         Pass
13.         {
14.             Cull Off
15.             CGPROGRAM
16.             #pragma target 5.0
17.             #pragma vertex vert
18.             #pragma fragment frag
19.  
20.  
21.             #include "UnityCG.cginc"
22.          
23.  
24.             struct PS_INPUT
25.             {
26.                 float4 position : SV_POSITION;
27.                 float4 color : COLOR;
28.                 float3 normal : NORMAL;
29.  
30.             };
31.  
32.             sampler2D _MainTex;
33.             float4 _MainTex_ST;
34.          
35.             sampler2D _XYZTex;
36.             sampler2D _ColorTex;
37.             float4 _XYZTex_TexelSize;
38.             float4x4 _Position;
39.  
40.             float _Size;
41.             PS_INPUT vert (appdata_full v, uint vertex_id : SV_VertexID, uint instance_id : SV_InstanceID)
42.             {
43.                 PS_INPUT o;
44.                 o.normal = v.normal;
45.  
46.                 //Compute the UVS
47.                 float2 uv = float2(
48.                             clamp(fmod(instance_id, _XYZTex_TexelSize.z) * _XYZTex_TexelSize.x, _XYZTex_TexelSize.x, 1.0 - _XYZTex_TexelSize.x),
49.                             clamp(((instance_id -fmod(instance_id, _XYZTex_TexelSize.z) * _XYZTex_TexelSize.x) / _XYZTex_TexelSize.z) * _XYZTex_TexelSize.y, _XYZTex_TexelSize.y, 1.0 - _XYZTex_TexelSize.y)
50.                             );
51.  
52.              
53.  
54.  
55.                 //Load the texture
56.                 float4 XYZPos = float4(tex2Dlod(_XYZTex, float4(uv, 0.0, 0.0)).rgb ,1.0f);
57.  
58.                 //Set the World pos
59.                 o.position = mul(mul(UNITY_MATRIX_VP, _Position ), XYZPos);
60.  
61.                 o.color =  float4(tex2Dlod(_ColorTex, float4(uv, 0.0, 0.0)).bgr ,1.0f);
62.  
63.                 return o;
64.             }
65.  
66.             struct gs_out {
67.                 float4 position : SV_POSITION;
68.                 float4 color : COLOR;
69.             };
70.  
71.  
72.          
73.             fixed4 frag (PS_INPUT i) : SV_Target
74.             {
75.                 return i.color;
76.             }
77.             ENDCG
78.         }
79.     }
80. }

Server output:

client output: