Tumbleweed
Correct me if i'm wrong, but the supernodes supposed to be harvested after season change. Digging them after every reboot is just exploiting incomplete game mechanics letting them to pop up when they meant to be empty. So why to care about it.
You get the mechanics wrong. They refill at server boot, but the content changes at season change.
So it's quite possible to see them empty at season change because they were dug out before and the changing season didn't change the content (this happens with some but not all changes).
In other seasons, you might have 2 chances to dig them.
If that's an exploit, it's been a known exploit by the devs for 7 years and nothing's been done to "fix" it, so I have to assume it's working as intended and making use of it is not an exploit at all.