I do not know what is going on.
Just to clarify; the fact that you are still able to build the corp building means that you are still running an older version, or that 1.7 didn't install correctly (eg installed 1.7 over the top of a previous version).
Not a stupid question at all. Looks like a good potential bug find. Can you confirm that the food bar doesn't move in the city if you repeatedly end turn?
Ie: even passively, the city doesn't grow?
Thanks for noticing this.