Poison Dart - Freeze/Frame Rate Drop

Not sure if this is new or not, or if anyone is seeing this, but there's a short freeze/frame rate drop when using poison dart. The game freezes temporarily when poison dart is cast is used, and returns to normal speed after the mob it's being used on has taken damage. I wasn't seeing this on any other character.

After doing some playing around, it seems like this does not occur if effects volume is set to 0. But I was seeing the freezes with the effects volume turned on at all.