Light Shading preview looks like a grid rather than beveled?

I’m using Toonboom Harmony Premium on my Microsoft Surface Pro tablet. I drew two (very sloppy) circles and applied light shading nodes on them as per Adam Phillips’ tutorial here: www.youtube.com/watch?v=l0bpes72pH8

but mine doesn’t end up looking beveled. Instead, it looks like a grid. Here’s a screenshot: http://i.imgur.com/bgdHswH.png

does anyone have any idea why this is happening?

Set the bevel size in the Normal Map module to 0. That fixed it for me.