> One example is memory. Deep mind doesn’t update it’s strategy when playing the same player repeatedly or even over the same game. It can operate at near peak human performance indefinitely but it avoids being exploited via deep understanding of the exact rules in play. It was also playing on the ladder under random names to avoid people developing specific counters.

This is because many games without perfect information have "rock-paper-scissor" situations. An AI designed without this in mind, lacking a source of randomness (or memory of the last encounter fed into the next game), is going to pick "rock" every time and start losing to the human who realizes and exploits this.