Very strange indeed, I can't fix it either. I wonder if it has something to do with your use of the "rotation", "heading" and "distance" parameters. Having never been able to predict where those will move my planet to, I've never really seen the point and don't use them, I just drag the planet. Perhaps some combination of those parameters and regular translation/movement has messed things up. I'm opening an issue in our internal tracker with the file attached, hopefully Matt or Jo can make something of it.
- Oshyan