Uchigaki is wearing ear plugs so he didn't hear the ref warn him at 10 seconds. You have to declare your extension. Apparently it doesn't just roll over.
It turns out Uchigaki went into his automatic extension as he was supposed to, burned through it as well, and could not hear the ref warn him at 10 seconds he was about to have a time clock violation because he had earplugs in his ears (from what was said). So he had a foul called and Ko got ball in hand.
The announcers initially had said he was having a foul called on him because he had not verbally called for an extension, which has not been required all tournament long as the extension is applied automatically (as it should be).
Given what actually happened and what was explained it was a legit foul.
Uchigaki is wearing ear plugs so he didn't hear the ref warn him at 10 seconds. You have to declare your extension. Apparently it doesn't just roll over.
The extension is supposed to be automatic and has been for the entire event so far. He supposedly burned through his extension already and did not have any more extensions when time ran out, and did not hear his warning due to the earplugs.