from wat I can see, sometimes I can recruit to 0 metal. And sometimes I have wat u said.
So I believe the metal production and the cost are not always exact. The production can be 99.97 or something. So when it shows 100 it's only 99.97. The same goes to the cost, maybe that time u need 10.01 but u only have 10 energy. So u can't use that.
I had the same problem, it needed 14 energy and I had 14 energy. And I couldn't jump, and when I reduced the squads to 13 energy I can jump for 14 energy instead
