quoting Nessari, Illúbequía, Seattle, Cascadia:

Any feedback from it on why it does that? Could be gravitational reasons certain orbits aren't tenable.

I really need to work out all the details of Šaol's star, so I can edit Aldebaran into it.

Nope. You just try typing in, say, 0.7 AU for Venus's orbit, and it will decide 0.65 was a much better choice and give you that. It often tries to screw with the eccentricity, too.