I doubt a pool would deliberately create their own fork, but if you have issues it can be surprisingly easy to inadvertently create a fork. If you manage to mine a few blocks while you're not connected to the rest of the network, and stay disconnected for more than a couple of hours, your client will refuse to recognise the main chain once reconnected.

Could even be as simple as the pool operator having a separate wallet for the pool and himself, he was mining KGC, and his internet link died for a couple of hours. Fork time.