Hi,
I'm new to the game, so not sure if this is a bug... But looks like one.
I accidentally tried placing a ghost of a transporter into a cliff (Shift + Left mouse click). This red cross appeared and persists even after save/load.
Best,
[0.17.66] Red cross remains when placing ghost on a cliff
Re: [0.17.66] Red cross remains when placing ghost on a cliff
It's scheduled for deconstruction. You can remove it with the deconstruction planer while holding shift.