Ortho Camera Wrong Depth?

Graphics
1

When I swtich to 100% Ortho then the result is messed up, any ideas why?

Ortho
result

protected void GenerateProjectionMatrix()
        {
            var presentationParameters = GraphicsDevice.PresentationParameters;
            var aspectRatio = (float)presentationParameters.BackBufferWidth / (float)presentationParameters.BackBufferHeight;

            // Combination of orthographic and perspective
            var width = 512f;
            var height = width / aspectRatio;

            _projection = Matrix.CreateOrthographic(width, height, _nearClipPlane, _farClipPlane);

            // Add slight perspective effect
            
            if (EnableMix)
            {
                var perspective = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45f), aspectRatio, _nearClipPlane, _farClipPlane);
                _projection = Matrix.Lerp(perspective , _projection, OrthoFactor);
            }
            else if (!OrthoOnly)
            {
                var perspective = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45f), aspectRatio, _nearClipPlane, _farClipPlane);
                _projection = perspective;
            }
        }

All I am changing is the boolean to enable the ortho-only mode.
The result is the same, no matter how near or far I am.