This news comes from NeoGaf user. Yusuke Naora from Square Enix has resigned from his post as Art Director. The source is Yusuke’s Twitter profile which, where he tweeted something in Japanese, which translated to his resignation news. It seems that Final Fantasy XV was his last project with the industry giants and the resignation will be effective since 30th September. (Yesterday, at the time of writing here).
Twitter Source here.
Neogaf Discussion here.