Ok, last unit was a non completed terraformed wall. It lived more than 20 minutes. japko could end the game and win by terraforming the wall (quite strange). As japko was ennemy from this wall, he couldn't see where to terraform so specs helped him and he could successfully end and win the game. I'm pretty sure he's the first person to ever win a game with a terraform.
There's a problem with terraforming. When it's 0% completed and you stop terraforming, it will die within 2 minutes as you said. But when you already started to terraform and completness is greater than 0%, even if you stop to terraform the terraform "unit" will never die.