I don't know, i just told what i read on guru. Let me see if i find it. Yes, here it is:
http://www.l2guru.com/forum/showpost.php?p=3105108&postcount=221
http://www.l2guru.com/forum/showpost.php?p=3105132&postcount=222
So, what i get from this, is that the skill was surely bugged at some time...