Freestyle for Blender

Originally a thread in the rendering section, someone suggested post here.

I have an intermittent problem with Freestyle rendering a hidden line, demonstrated by this animation:

The problem first appears at 4s into the animation, and then flickers on and off a few times.

I saw another post here with similar problems, and the advice was to subdivide the object, which kindof works for me too (creates other, more subtle artefact), but I want to understand if this is a known bug and if there might be a better way to fix it.

The problem was discovered using 2.73a, and also occurs in 2.74 RC (Linux x86_64).

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