Weird artifact in blender render I'm trying to recreate a spa water bottle, to get some Blender practice. An example of the bottle:


Around the bottle are some round carvings. I created these with a Difference Boolean with a torus. I've hidden these torusses (tori?) from the view and renderer.

However, when rendering (with Cycles Render), I see some weird shape, like one of the torusses isn't really hidden. When looking with the rendered viewport shading in 3D view, I don't see the extra torus (which is what I expect).

What could this be?

Modifiers applied to the bottle, in order: subsurf, 8 booleans, solidify.

The rendered view (with unwanted artifact):


The viewport view:


EDIT:
I've doublechecked all modifier visibilities and the visibilities of the torusses themselves, and I don't see anything odd. See the image below.

Additional info, I made the torusses by extruding a circle over a circular beziercurve, and creating a mesh from that.

EDIT2:
I've added the Blend file to the top of this question
The problem is caused by a small discrepancy between how the booleans are applied on a level 3 subdiv and a level 4 subdiv. Drop your render sub-div level down to 3 or move the torii so they create the correct behaviour with level 4 subdiv enabled in viewport.