I think what you mean is that the Moon's orbit around Earth produces a variation of the curvature of the Moon's Solar orbit. But that this variation is less than the curvature of the Earth's orbit (mean orbit of the Moon). So this means that the Earth's curvature +/- the variation (wobble) is still always positive (i.e. towards the Sun).

Strange, but I don't remember anyone pointing this out before. It seems fair enough, though, now I think about it. The magnitude of this wobble is only 0.2% of the radius of the Earth's orbit and rough sketches always exaggerate this and would suggest otherwise.

This won't always happen for all planets and moons. If the Earth were much more massive and the Moon had the same orbital period then its orbit could be much greater than 350,000km. That would produce a proper 'curly wurly' orbit.