Only horizontal Lines are Drawn with Debug.DrawLine in GameView

I try to create a Grid with Unity. For Debugging Purpose, I want to Draw the Boxes with Debug.DrawLine.

//Drawe Grid Box Lines
//Horizontal Lines
Debug.DrawLine(GetWorldPosition(x, y), GetWorldPosition(x + 1, y), Color.white, 100f);
Debug.Log("Line Drawn: " + GetWorldPosition(x, y) + ", " + GetWorldPosition(x + 1, y));
//Vertical Lines
Debug.DrawLine(GetWorldPosition(x, y), GetWorldPosition(x, y + 1), Color.white, 100f);
Debug.Log("Line Drawn: " + GetWorldPosition(x, y) + ", " + GetWorldPosition(x, y + 1));

In the SceneView, it's rendering fine:

In the GameView instead, it only rendering the Vertical Lines:

Does anyone have an idea why only the Vertical lines are printed?

The Debug.Log shows me one correct Line for all Lines, Vertical and Horizontal.

Thank you