Final Gambit - Bug

"The move's side effect is not considered as inflicting damage to the user, and so if the user is holding a Focus Band, Focus Sash, or has Sturdy, it will not activate and the user will still faint. However, the move inflicts damage to the target, and so the target's Focus Band, Focus Sash, Sturdy, and/or Endure can still trigger if applicable, so that the target will be left with 1 HP."

source: https://bulbapedia.bulbagarden.net/wiki/Final_Gambit_(move)

Tested with my ninjask after it use the move the other poke died, but my ninjask was still alive while my focus sash "broken".

It's is a bug that should be even banned from ladder, since ninjask can use final gambit (which is a move who always will do the damage based on the user hp), kill the enemy poke survive with 1hp and possible use baton pass, while u still will have a poke alive for various situations.