How can I get rid of a visual flaw in my logo. It appears to be coming from 3D effect

I'm creating a logo that is text-based. When I add the 3D Bevel and Extrude effect, it makes an odd-looking glitch on one of the letters.

This logo is something I created in Photoshop then had to mimic in Illustrator so that I can give my client a vector format of the logo (rookie mistake!). So, I had to manipulate each letter to take on the shape of the one I'd made in Photoshop. Each letter is on it's own "layer" (is that a thing in Illustrator?) so that I could space them appropriately and edit each one separately. The letter in question was stretched both length and width-wise. There are no flaws in the letter before I apply the 3D effect. I've tried saving different formats of the file as well as undoing and redoing the effect on that letter by itself. I thought maybe it was just an issue with Illustrator, so I opened the file on another machine and saw the same flaw. This problem is not happening to any other letters.

Here is a photo of it: http://ift.tt/174NJSH

The issue is on the top curve of the "S".

And here are my settings for the effect: http://ift.tt/1vGjE1t

What am I doing wrong?