Good question Roman. No doubt the sudden change in direction is due to the Comet-Earth geometry changing during the months as the comet orbits the Sun, and Earth orbits the Sun, but at different rates. The comet looks to be experiencing some kind of retrograde motion similar to what happens with Mars when the Earth overtakes the planet/comet in it's orbit.
I'm guessing that's what's happening here although an expert in orbits would be able to explain it better.
I understand it but not at all.
More simple question. When I look at the trajectory of Mercury, I sometimes see #1 or #2 kinds of trajectory.
I can somehow explain #1, but what about the #2, the same as the C/2006OF2 ?