[0.77] Bug puts buildings on wrong terrain; for example a fortress on forest

This bug erroneously places some buildings on the wrong terrain. For example, I can put a great mill on forest terrain. It doesn't actually place, but I am also limited from placing it anywhere else.

Reproduction steps:

1) Place a building where it belongs, for example a merchant.

2) Select another building in the building list. Click the building in the list again to de-select it.

3) Select a 4-tile building

Result: The final 4-tile building appears above forest terrain instead of normal terrain. http://i.imgur.com/5z9wt.jpg

 Note: the steps must all follow each other. If you don't you won't see the bug.