Doesn't make sense. If the standard fusion rifle nerf hit it, then the Sleeper Simulant would need to charge even quicker than before. Bungie reduced the damage of the high impact FR, but decreased their charge time to compensate. The nature of the Sleep Simulant makes it the hardest hitting FR in the game. So it shouldn't charge slower, if it was the general nerf. It's either a bug or a ninja nerf.