As soon as the animation for the little guy makes it out to the building site for mines/wells/wheat fields (all I have tried as I am short on licences) the item does not build. The building site disappears and the build queue disappears before 1% completion is displayed.
I have restarted the browser, logged out and back in, and cleared both flash and browser cache. The bug persists.
Edit- The only way to make it finish buildings is to press the little blue gem thing that represents you premium currency before it disappears.
Edit 2- But even then the items built with the premuim gems will disappear in the time it took me to make the first edit.