My first theory was that they played something like the diagram instead of capturing the 5 stones at move 190 but it is still odd since
would have been sente if 
.My second theory is that they played as in the next diagram. That is white played the ko threat
but black plays 
before finishing the ko, then white kills the corner in gote. White could play 
differently but this way eliminates black's ko threats. It could be some nine-dan-shenanigans, black making a good forcing move when white won't maximize the points locally. If there was no concern about ko threats, white could respond to
as follows.The schedule of the tournament suggests that the games were first played and then broadcasted later. That is gotoeveryone displays two dates as with NHK cup. Maybe there is some chance of finding a recording? It would be rather interesting, especially if it is the case that the stones slide, it is hard for me to imagine how white could think he could simply capture the 5 stones and already have killed the corner. The remaining moves are also much smaller than living the corner. I guess anything could be possible if the stones start moving
