Master Duel Surrender Exploit. Konami, please fix this.
This exploit allows you to surrender the opponent.
You can read more here: https://guidedhacking.com/threads/yu-gi-oh-master-duel-hack-surrender-opponent-in-pvp.19557/
Video of the exploit in action: https://www.youtube.com/watch?v=waJ_XCXv2x4