XNA 4 VertexPositionTexture triangleStrip sporadically disappearing - xna-4.0

Question

I am drawing a traingleStrip using VertexPositionTexture and BasicEffect that extends from the first person perspective of the screen out a certain distance on the Z axis.
In a loop I pass start and end vectors to this code to create my vertices.
public VertexPositionTexture[] vertices = new VertexPositionTexture[4];
private int xPos = 4;
public waypointLineSegment(Vector3 startPoint, Vector3 endPoint)
{
this.texture = texture1;
vertices[0].Position = new Vector3(endPoint.X - xPos, endPoint.Y, endPoint.Z); //Upper Left Point
vertices[0].TextureCoordinate = new Vector2(0, 1);
vertices[1].Position = new Vector3(startPoint.X - xPos, endPoint.Y, startPoint.Z); //Lower Left point
vertices[1].TextureCoordinate = new Vector2(0, 0);
vertices[2].Position = new Vector3(endPoint.X + xPos, endPoint.Y, endPoint.Z); //Upper Right Point
vertices[2].TextureCoordinate = new Vector2(1, 1);
vertices[3].Position = new Vector3(startPoint.X + xPos, endPoint.Y, startPoint.Z); //Lower Right Point
vertices[3].TextureCoordinate = new Vector2(1, 0);
}
I initialize like this:
protected override void Initialize()
{
graphics.GraphicsDevice.RasterizerState = RasterizerState.CullNone;
basicEffect = new BasicEffect(graphics.GraphicsDevice);
base.Initialize();
}
I render the plane in this way:
Vector3 transformedReference = Vector3.Transform(new Vector3(0, 0, 10), aRotationInt);
Vector3 cameraLookat = firstPersonVector + transformedReference;
view = Matrix.CreateLookAt(firstPersonVector, cameraLookat, Vector3.Up);
basicEffect.View = view;
foreach (EffectPass pass in basicEffect.CurrentTechnique.Passes)
{
pass.Apply();
graphics.GraphicsDevice.DrawUserPrimitives(PrimitiveType.TriangleStrip, allVertices, 0, 2);
}
This works great. But, when I apply a rotation to the view, the strip will disappear every once in a while. Then it will reappear with a single degree of more or less rotation applied.
I cannot find a pattern. It might happen at 37 degrees or 315 etc. I have set the GraphicsDevice RasterizerState to CullMode.None. Can anyone help?: