This is one of the reasons I rarely participate in temp missions that reward planet artifacts.
I accidentally placed this artifact on one of my planets, then went to extract it, and I cannot. A artifact that we used lots of energy and artifacts to obtain, we have to demolish it in order to remove it from the planet, which is totally ridiculous.

It's by design.

If it was definitely an accident, contact Dan using the in-game reporting feature, and see if he'll remove it for you.

That.

Tho i wouldn't mind Dan changing it so that all NON upgraded artifacts/structures can be extracted.