Using Itween with Unity 2D, sprite flips over while using orienttopath

I'm having trouble getting my sprite to consistently orient correctly. I've done the trick where you parent the sprite to a rotated game game object, which mostly works, but when the sprite takes certain turns, it flips over(the z rotation goes from 0 to -10 or so). The actual orientation of the sprite stays the same, but it looks bad when the 2D objects flips over like that. Is there something I can do to stop this?

This is my moveto function.

 iTween.MoveTo(gameObject,iTween.Hash("path",path,"orienttopath",true,"speed",speed,"easetype",iTween.EaseType.linear,"oncomplete", "GenerateRandomPath"));