All of the text is in SVG <textPath>s with style text-anchor:middle, and so should be roughly centered in each sector.

1. 'Two lines #1' has two <tspan>s in a single <textPath>. The text-anchor:middle is ignored on Safari. If you delete either one then the other centers correctly.
2. 'Two lines #2' has two <tspan>s in a separate <textPath>s, but still in the same <text>. The <tspan> dys are still summed on Safari, even though they're in separate <textPath> elements.
3. 'Two lines #3' has two separate <text> elements and renders fine on Safari.