When AI gets strong enough (and it seems like it has already), it will just tenuki everyone all the time, while winning. Sounds like exactly what's happening already. It's past the event horizon for human understanding.
AlphaGo creators could "rewind" the whole program state to that move and inspect the tree search probabilities according to the board states it looks through to find a list of board states that generate a cumulative highest probability of wining by doing a move in that exact odd spot.
My guess would be that while humans tend to put stones with a single, double, or sometimes triple "reason", or in AI words, "high probability of local effectiveness in upcoming several turns", AlphaGo, with his ability to see further, can see past the local effectiveness into more global effectiveness and higher probability of winning further down the road.
In other words, those tenuki moves might actually be past the event horizon of human understanding, but only if inspected by looking at them and thinking ourselves. If we use AlphaGo itself, it should be possible to find out the reason for every single tenuki it will ever do.
I think this phrase is going to pop up more and more frequently.
It is a misunderstanding that has been breathlessly repeated by futurists and transhumanists for years.