Hey!
Thanks for your feedback and for pointing this out. What you're experiencing isn't a bug, it's actually intended. When you deselect the "Go to Nauvis in a new game" option, the game starts on a simple surface that isn't linked to Nauvis. This means you can't launch a rocket with a starter pack for your first space platform.
The option is enabled by default so players can enjoy the full progression of the game. If you want to play the extension normally, you need to start a new game with this option enabled.
The issue isn't related to the bug mentioned on the forum. That bug is about scenarios missing certain code that the "Main Game Freeplay" has.
I get that you prefer to start with the crash site for fun. When I get back to working on my mods, I'll look into adding the crash site when requesting to stay on Nauvis, but it won't happen right away. Hope that clears things up!