Nomands game not ending

When playing a PVE multiplayer game, in this case using Sorian AI, some of the AI's nomad buildings are not getting destroyed. While all hitpoints have gone, and the UI elements including HP's and name are not viewable (or selectable) anymore; the undestroyed 3d model is still on the map. No matter what you do, ground fire, nukes or whatever, there's no way to destroy the structure.

This results in a supremacy game not ending correctly since the unit is still there.