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:

but mine doesn’t end up looking beveled. Instead, it looks like a grid. Here’s a screenshot:

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.