WoW errors on knockbacks

[Grazzia]

WoW Freakz link: https://www.wow-freakz.com/spells.php?spell=195457&&name=grappling-hook; https://www.wow-freakz.com/spells.php?spell=781&&name=disengage; https://www.wow-freakz.com/spells.php?spell=152150&&name=death-from-above
Bug description: These spells causes wow error instantly when you try using it on a knockback. Example spells, if you use it when its being casted on you youll cause wow error: https://www.wow-freakz.com/spells.php?spell=200284&&name=tangled-web; https://www.wow-freakz.com/spells.php?spell=211785&&name=shattering-stomp; https://www.wow-freakz.com/spells.php?spell=198073&&name=earthshaking-stomp; https://www.wow-freakz.com/spells.php?spell=232722&&name=slicing-tornado and so on, all similar spells vs the mentioned spells. Even after deleting cache its happening.