What is wrong with this mesh editing code?

I'm building a procedurally generated mesh, and need to fix normals at the chunk edges. I wrote this method to solve this for me, however, even tho in my Debugger screen the 2 vertex in world space are in the very same position, this code does not find them somehow. I mean the Vector3.Distance will be some random number, and sometimes I get crazy values which is not even the reality. For example when 2 vertices has the same position (-4, 0, 0) in world space, this code fids something (12, 0, 0) and I have no idea how.

 void MixNormals(VoxelChunk chunk1, VoxelChunk chunk2)
     {
         Mesh mesh1 = null;
         Mesh mesh2 = null;
         if (chunk1.chunkObject.GetComponent<MeshFilter>() != null) mesh1 = chunk1.chunkObject.GetComponent<MeshFilter>().mesh;
         if (chunk2.chunkObject.GetComponent<MeshFilter>() != null) mesh2 = chunk2.chunkObject.GetComponent<MeshFilter>().mesh;
 
         if (mesh1 != null && mesh2 != null)
         {
             Vector3[] vertices1 = mesh1.vertices;
             Vector3[] vertices2 = mesh2.vertices;
             List<Vector3> normals1 = new List<Vector3>(mesh1.normals);
             List<Vector3> normals2 = new List<Vector3>(mesh2.normals);
 
             for (int i = 0; i < mesh1.vertexCount; i++)
             {
                 for (int j = 0; j < mesh2.vertexCount; j++)
                 {
                     float dist = Vector3.Distance(chunk1.chunkObject.transform.position + vertices1[i], chunk2.chunkObject.transform.position + vertices2[j]);
                     if (dist <= vertexMergeMaxDistance)
                     {
                         normals1[i] = normals2[j] = (normals1[i] + normals2[j]) / 2;
                     }
                 }
             }
         }
     }