Very easy to reproduce. Just select the HQ, and hold it where you would place it without placing it. Memory usage increases at about 150MB/s until the process can no longer allocate more memory and crashes. It does not seem to matter whether the game is paused or not.
This also seems to happen with smaller buildings, although at a much slower rate.
http://imgur.com/K0U8kfl
Version is 0.0.4853.
