Does nasty blade and filthy blade stack on legion?

LonlyGamerX

I know in the past there was a bug with legion and those add ons called the infinite mend and im not trying to make it happen again. I just want to know if they stack cuz it could help a lot in a match. When i ask streams (like no0b3 or Tru3ent) they say as long as it doesnt say do not stack they stack. I just want to know if this is true or not. And why on some add ons they say if they stack or not but on others there is no infomation