2d artefact gap between tiles

I have issue which u can see on left image when orthographic size of my camera is an integer. If orthographic size is integer+0.5 than its ok: right image.

Size of my camera changes automatically by formula

camera.orthographicSize = camera.pixelHeight / 2.0f;

Width and height of tiles meshes and textures is 16.

1 generate 1 mesh, and for every tile i make quad of 4 new verticles:

 for (int i = 0; i < _w; ++i)
         {
             for (int j = 0; j < _h; ++j)
             {
                 if (data[i,j] != null)
                 {
                     SetTile(new XY(i, j), data[i,j].GetId());
                 }
             }
         }
 
 public void SetTile(XY pos, int tileId)
     {
         //    ->
         //  1    2
         //  *----*
         //  | \  |
         //  |   \|
         //  *____*
         //  3    4
         int index = (pos.x * _w + pos.y) * 4;
 
         _vertices[index] = new Vector3(pos.x * _tileSize, _depth, pos.y * _tileSize);
         _vertices[index + 1] = new Vector3(pos.x * _tileSize + _tileSize, _depth, pos.y * _tileSize);
         _vertices[index + 2] = new Vector3(pos.x * _tileSize, _depth, pos.y * _tileSize + _tileSize);
         _vertices[index + 3] = new Vector3(pos.x * _tileSize + _tileSize, _depth, pos.y * _tileSize + _tileSize);
 
         _normals[index] = Vector3.up;
         _normals[index + 1] = Vector3.up;
         _normals[index + 2] = Vector3.up;
         _normals[index + 3] = Vector3.up;
 
 
         Rect uv = _atlas.spriteDefinitions[tileId].uv;
         _uvs[index] = new Vector2(uv.xMin, uv.yMin);
         _uvs[index + 1] = new Vector2(uv.xMax, uv.yMin);
         _uvs[index + 2] = new Vector2(uv.xMin, uv.yMax);
         _uvs[index + 3] = new Vector2(uv.xMax, uv.yMax);
 
         int triangleIndex = (pos.x * _w + pos.y) * 6;
         _triangles[triangleIndex] = index;
         _triangles[triangleIndex + 1] = index + 3;
         _triangles[triangleIndex + 2] = index + 1;
 
         _triangles[triangleIndex + 3] = index;
         _triangles[triangleIndex + 4] = index + 2;
         _triangles[triangleIndex + 5] = index + 3;
     }

What am i doing wrong? Help me please.