Lines in wood grain rendering, not sure of cause?

[Anonymous]

Sometimes when I'm rendering I get these close lines that appear, they look like part of the grain, but they don't show up in similar renderings.  Any idea what is going on?

Correct versionLines showing up?

[I_Forge_KC]

Is it a different lighting style? It almost looks like the reflection of the grid light (or something similar) shining back by the gloss of the wood finish (what gloss there is). 

[Anonymous]

Don't think so. The only difference I can figure is it was rendered on different PC's, but it's the same file.  I've tried moving the light around and redoing the material but it always stays with the lines.

[I_Forge_KC]

If you change to something like gloss plastic what does it look like?

[Anonymous]

Normal, no lines showing

[Anonymous]

For some reason, when I duplicate the walnut material, then re-add it to all the parts, it seems to fix it?  I adjusted no settings after duplicating.