https://steamcommunity.com/app/27585...4400736890806/
And yet, like one giant fucking miracle, this guy has literally the same thing happen to him that I do, note the date.
Oh, and here's one from January for good measure:
https://steamcommunity.com/app/27585...6179573270334/
Wether or not you could move or build your bases in the freaking sky is not the point, the point is that terrain is respawning for one reason or another, has been doing so since at least August 2017. That means if you built anything that would conflict with pre-existing terrain when this bug hits, you're fucked.