Issues with Low Poly Shader on Mesh

I am trying to make a randomly generated mesh with a low poly look to it, and have made a shader using this tutorial: https://www.youtube.com/watch?v=e3oYQL0oDEs. I also created a script to procedurally generate a mesh. Unfortunately, when I run it, this happens:

My issue is the random black triangles everywhere, and when I view the scene and pan around while its running, the triangles change in color. Ideally, I would want the mesh to have this same look, except for without the random black triangles.

The project uses a Lightweight Render Pipeline and uses the script pasted below. I made the script it's own object in the scene and set the xSize and zSize to 20. I also made a PBR Shader with this ShaderGraph:

Any help is appreciated. Here is the Mesh Generator Script:'

 public int xSize = 10;
 public int zSize = 10;

 Mesh mesh;
 Vector3[] vertices;
 int[] triangles;
 Color[] colors;

 float minTerrainHeight;
 float maxTerrainHeight;

 void Start()
 {
     mesh = new Mesh();
     GetComponent<MeshFilter>().mesh = mesh;

     CreateShape();
     UpdateMesh();
 }

 void CreateShape()
 {
     vertices = new Vector3[(xSize + 1) * (zSize + 1)];

     for (int i = 0, z = 0; z <= zSize; z++)
     {
         for (int x = 0; x <= xSize; x++)
         {
             float y = Mathf.PerlinNoise(x * .2f, z * .2f) * 3.5f;
             vertices[i] = new Vector3(x, y, z);

             if (y > maxTerrainHeight)
             {
                 maxTerrainHeight = y;
             }
             if (y < minTerrainHeight)
             {
                 minTerrainHeight = y;
             }

             i++;
         }
     }

     triangles = new int[xSize * zSize * 6];

     int vert = 0;
     int tris = 0;

     for (int z = 0; z < zSize; z++)
     {
         for (int x = 0; x < xSize; x++)
         {
             triangles[tris + 0] = vert + 0;
             triangles[tris + 1] = vert + xSize + 1;
             triangles[tris + 2] = vert + 1;
             triangles[tris + 3] = vert + 1;
             triangles[tris + 4] = vert + xSize + 1;
             triangles[tris + 5] = vert + xSize + 2;
             //yield return new WaitForSeconds(0.1f);

             vert += 1;
             tris += 6;
         }
         vert += 1;
     }

     Color currentColor = new Color();
     colors = new Color[vertices.Length];

     for (int i = 0, z = 0; z <= zSize; z++)
     {
         for (int x = 0; x <= xSize; x++)
         {
             if (i % 3 == 0)
             {
                 float side = Random.Range(0f, 0.6f);
                 float opac = Random.Range(0.7f, 1f);
                 currentColor = new Color(side, opac, side, 1);
             }
             colors[i] = currentColor;
             i++;

         }
     }
 }

 void UpdateMesh()
 {
     mesh.Clear();
     mesh.vertices = vertices;
     mesh.triangles = triangles;
     mesh.colors = colors;


     mesh.RecalculateNormals();

 }

'