Black has a piece stacked and blocking White's connection. On Black's turn, she moves the stacked piece to make a connection for herself. And by moving the piece, White's connection is unblocked and re-established.
Since both players now have a connection, is the game a draw? Or since it was Black's turn, does she win?
It's likely an oversight. He probably checks for connections after every move in white/black order. The first one he finds is the winner. This is an interesting situation that is overlooked in the rules. In other Gipf games, the player whose turn it is "goes first" (eg Gipf,Yinsh). So I suspect the official ruling will be that Black should in fact win.