Hello Joe,
Thanks for your post and image, not every spline type is design for all characters, below is some comments for the spline type.
/// <summary>Default SplineType provided in PositionStyle.</summary>
Default = 0,
/// <summary>This SplineType will label the text in a line type without any spling effects, this kinds of type will gain
/// better performance compare to StandardSplining.</summary>
None = 1,
/// <summary>This SplineType will label the text in a standard Spline way, it will have much better outlook in some situations
/// while it will lose slightly some performance.</summary>
StandardSplining = 2,
/// <summary>
/// This SplineType will force the labe text using Spline way, otherwise the label won't display.Usually it is just used for Asian languages
/// like Chinese or Japanese.
/// </summary>
ForceSplining = 3,
If it's not working good for Arabic language, I think you need to set it to none to avoid the problem. Also we will do some research and try to make if fit mor situation.
Sorry for inconvenience.
Regards,
Gary