Oh yes John, I mixed up the Jules Verne challenge and the Ultimatlantic, I'm sorry.
Yes, on the Jules Verne challenge, and on all races crossing the antemeridien, for a while, the tail of the boat is wrong and is making a whole circle around the planet, this is the white line that you see.
When the last point of the tail will be on the same hemisphrere than the boat, this line all around the planet will disappear.
This is a kind of "cosmetic" bug that is a bit tricky to solve, and we think it's not wotrh it to spend to much energy on it.
As you see, the game is not perfect, but however we can sail, race and have fun despite these little imperfections.
We hope you'll understand, although I've understood you like perfection...
(By the way, I think there is also a little bug remaining when crossing the antemeridian, one iteration get lost in translation, we should work on it as well...)
Best regards
Blaise