Ok, having watched the replay I don't know whether to laugh or cry ...
At around 30 minutes into the game, the AI decided to build a strider factory and queued up a Paladin - and probably stopped using the other factories to get the Paladin built more quickly.
However ... the strider factory was not connected to the power grid. A few minutes later, a constructor arrived and built a wind power plant near the strider factory, which nearly, but not quite, touched the power grid of the factory. A few minutes later, another constructor arrived, and built another wind power plant, which nearly, but not quite, touched the power grid of the factory. This repeated about a dozen times, surrounding the strider factory with wind power plants, none of which were close enough to connect to the factory. And so the paladin never got built. And the AI excessed half a million metal. And after a while, all mobile AI units had been destroyed. The AI watched its defenses being overrun, faithfully waiting for the Paladin who never came.