I've seen this before, and this has always baffled me. Occasionally while manipulating an object in Illustrator, I end up with a path which seems like it's been broken — it shows a dramatic horizontal gap, as if there's a point far to the left or right of the actual path. When this shows up, it's almost always intermittent, disappearing on zoom. In the example I've created, shifting the object's position causes this gap to disappear and reappear.
What's going on here? Is this path corrupt? If so, is there any hope of fixing it? In this case I could recreate easily, but sometimes the object is something it took a long time to build.