I’ve done a fair bit of 2D interface work using outlined objects and the lines are a real pain to get right. What is bothering me here is that the line is the highest resolution and highest contrast component of the actor. Essentially the outer edges of the object, which are further from the eye than, say, the belly of the deer, attract too much attention and pop off the screen - making the actor look flatter or concave in various areas. The line flattens the art, stealing some depth from the viewer’s perspective yet the shadows that are cast don’t reflect the same flattening - so I’d guess that this scene in motion would be more confusing to the eye than a still image.
It could be interesting to try the line as a slightly darker shade of the actor’s color - maybe even with a bit of blur so the edges aren’t so hard.