With todays update you will lose the battle if you use Destiny Bond as your last move and both pokemon faint. So considering that the only problem is that the Boss is using the wrong text after losing.
'If the player’s final Pokemon used Selfdestruct, Explosion, Destiny Bond, or Final Gambit, and both players’ final Pokemon faint as a result, the player who used the move loses that game.'
https://pokemonrevolution.net/forum/topic/3146-update-logs/?do=findComment&comment=918019