Nightsister acolyte Crit chance not stacking Properly

You did make sure you got her special critical chance to above 50% or higher right?

The video you have attacked you used her Special ability which deals special damage not physical damage so the crit chance will be based off of her special critical chance not her physical critical chance.

My NS Acolyte Special critical chance is ~2.8% lower than her physical critical chance.

So if you got her physical critical chance to 50.48% her special critical chance would be about 47.7% meaning with her unique and CC up it would be 97.7% leaving a window in to not crit.