On 2.0 w/ the Enable Feature Flags mod, without the Space Age mod enabled, and possibly due to something terrain related from Pyanodon mods, it is possible that landfilling some water will result in Empty Space, as in off the planet, with stars in the background. I'm not sure if the Pyanodon part is relevant, I haven't tried seeing if I could repeat it without Py. Note that not all water did this, I only found a relatively small patch that did, though I did not go around landfilling everything to check how much it really was.

Example-
https://i.gyazo.com/128cedfdeb6cc8ccb905d180da96b2c9.png

Reloading a save before I landfilled a hole into the planet and disabling NiceFill fixed the issue. Though now the ground is ugly. Oh well.