Mesh visible in editor but not build

Hello, I'm currently trying to generate a mesh at runtime and have been successful, I suppose. However, I cannot figure out why mesh generation doesn't work in the built project, while functioning in the editor, even in playmode. To be more accurate, the problem has something to do with displaying the mesh.

Below is the function for generating the mesh:

     Mesh GenerateMapMesh()
     {
         List<Vector3> mapMeshVertices = new List<Vector3>();
         List<int> mapMeshTriangles = new List<int>();
 
         List<Color> mapMeshVertexColors = new List<Color>();
 
         #region Calculating Mesh Data
 
         for (int x = 0; x < mapSize.x; x++)
             for (int z = 0; z < mapSize.y; z++)
             {
                 Vector3 hexagonPosition = hexagonPositions[x, z];
 
                 #region Triangulating
 
                 Vector3 height = CalculateHexHeight(noiseMap[x, z]);
 
                 for (int t = 0; t < 6; t++)
                 {
                     GenerateTriangle
                     (
                         hexagonPosition + height,
                         hexagonPosition + hexagonCorners[t] + height,
                         hexagonPosition + hexagonCorners[t + 1] + height,
 
                         ref mapMeshVertices, ref mapMeshTriangles
                     );
 
                     // 3 is the vertex count
                     for (int cc = 0; cc < 3; cc++)
                         mapMeshVertexColors.Add(GenerateColor(noiseMap[x, z]));
 
                     // If this hex should be elevated, then a quad will be
                     // generated from the elevated and non-elevated vertices
                     if (height.y - 0.075f > 0)
                     {
                         GenerateQuad
                         (
                             hexagonPosition + hexagonCorners[t],
                             hexagonPosition + hexagonCorners[t + 1],
 
                             hexagonPosition + hexagonCorners[t] + height,
                             hexagonPosition + hexagonCorners[t + 1] + height,
 
                             ref mapMeshVertices, ref mapMeshTriangles
                         );
 
                         // The quad has 6 vertices (2 trianlges)
                         for (int cc = 0; cc < 6; cc++)
                             mapMeshVertexColors.Add(GenerateColor(noiseMap[x, z]));
                     }
                 }
 
                 #endregion
             }
 
         #endregion
 
         #region Setting Mesh Variables
 
         Mesh mapMesh = new Mesh();
         mapMesh.name = "HexMapMesh";
 
         mapMesh.vertices = mapMeshVertices.ToArray();
         mapMesh.triangles = mapMeshTriangles.ToArray();
 
         mapMesh.colors = mapMeshVertexColors.ToArray();
 
         mapMesh.RecalculateNormals();
 
         #endregion
 
         return mapMesh;
     }

Most of the above function is irrelevant, but just in case there is a need for someone to view the entire thing, I will not remove any part of it.

Back to the point, my calculations are accurate, the lists are populated properly, I've tested by instantiating objects in their place. The problem I mentioned is using lists, if I use an array and populate it manually it works in the editor and in the build. The following is an example:

     Mesh GenerateMapMesh()
     {
         #region Calculating Mesh Data
 
         #region Calculating Vertices
 
         Vector3[] vertices = new Vector3[3];
         vertices[0] = Vector3.zero;
         vertices[1] = Vector3.up;
         vertices[2] = Vector3.right;
 
         #endregion
 
         #region Calculating Triangles
 
         int[] triangles = new int[3];
         for (int t = 0; t < triangles.Length; t++)
             triangles[t] = t;
 
         #endregion
 
         #endregion
 
         #region Setting Mesh Variables
 
         Mesh mapMesh = new Mesh();
         mapMesh.name = "HexMapMesh";
 
         mapMesh.vertices = vertices;
         mapMesh.triangles = triangles;
 
         mapMesh.RecalculateNormals();
 
         #endregion
 
         return mapMesh;
     }

Of course, I've tried using arrays instead of lists and painstakingly do the exact same calculations with them. I tested it thoroughly but got the same results, worked in the editor, but not in the build.

I tried doing this in different unity versions, I tried unity 2019 and 2018 but still got the same results, currently, I'm using unity 2020.1. I also tried to manually move the lists' values to arrays but it didn't work.

After doing further testing, I determined that the vertices and the triangles are assigned to the mesh, but like I said, they aren't displayed.