Emancipation Gate Issue

[Sartain]

In a regular single player game, I've researched all necessary techs, reached the appropriate Affinity level in Supremacy and cleared all the other steps of the quest, which is now telling me to construct the Emancipation Gate.
But, when I try to queue it up in any of my colonies, the worker placement just gets all screwy (the circles stay but the worker icon disappears and the circles move to other tiles) and the Gate won't queue.

 

[Nelson Minar]

Just checking; you know the Emancipation Gate has to be placed on a tile, right? It's not like ordinary buildings, it's more like a tile improvement that's built from your city. That totally confused me at first. It has a sort of unique UI, but from your description maybe that's broken for you.