iTween + Orthello 2D Layer/Depth Issue

Here's the situation: I've got two Orthello2D Sprites, a tile and a player. When the user clicks the tile, it calls iTween.MoveTo on the player's GameObject to move them to that position, but for some reason when the player sprite gets near it's end-point, it moves behind the tile, then after the tween is over it pops back in front again.

As far as I can tell the actual Depth parameter of the OTSprite doesn't change. If I remove the tween, and set the transform directly, everything is fine and there are no layer/depth issues. I've tried editing every possible required and optional parameter in iTween.MoveTo and I just can't figure it out.

Has anyone experienced a problem like this before?