Hello,
I also have the same issue. It happens when you stun aliens and they wake up. I don't really know why yet because I have already seen aliens wake up.
I suspect it happens when you stun more than 1 or 2 aliens. In my current game, I am trying to stun 3 aliens on a map where there are 8 and this bug is almost systematic when I stun aliens at the begginning. The only way I found to finish the map is to kill aliens first then stun the 3 last.
Here is the log :
http://pastebin.com/ECqLfJQUI have had a look with the debugger and it seems it is a bug with the alien state. When he wakes up, his state is not changed (still 0x43) so the sanity check that an entity is alive before killing it fails. I have not seen yet how the messages are sent to the server so I could not go further. I will have a look deeper when I can.
I have posted the log with the developer option. If needed, I have 2 other logs of the same problem (but without developer var set).