Star Wars Jedi the fallen order not so fast achievement not progressing

Im playing on xbox and doing the last achievement and its not so fast where i have to defeat 25 enemies while they are under the effect of empowered slow.

The difficulty was on jedi knight when i started its and got idea that if i lower it to story mode then the enemies have longer to detect meand now its stuck on 64 procent nad tried to go back to difficulty i was and tried restarting the game but didnt work then a restared the console aslo it didnt work.

any suggestions?