Just found something in the sky...

I get things like this as well.  From what I can tell, all of the artifacts (usually just progress and health bars) in the black areas to the left and right and those in the no build zone are actually things from other asteroids.  I'm assuming all asteroid grids are simply a part of a single large grid. Are you using the zoom mod?  I do and have wondered if it has made these things visible where they might not otherwise be.

Edited July 1, 2022 by ONIZone

I've said something about this before. It is some sort of visual bug from the planetoids being all part of one larger grid. You'll see most of the time things like the conveyoring of items, harvesting / building / deconstruction animations, health bars of stuff near by, and what not near the edges of your planetoid if you use alt + s and zooming way out.