Wynn Resorts Ltd. is disputing a key argument by dissident Wynn board member Kazuo Okada as Okada presses to be reinstated as the company’s largest shareholder. As he heads toward an October court showdown with Wynn Resorts, Okada has challenged the company’s move in February to redeem his shares and replace them at a 30 percent discount with a $1.9 billion note.