Kitava sunder effect mtx bug

So,i have an issue with an mtx i just bought today,kitava sunder effect mtx is bugged ,when i apply this mtx to my sunder skill on my warrior the skill doesn't work properly anymore ,i will post a link here with a video i made on youtube with this issue ,as you see in the video when i use the skill 1 time it works and 1 time doesn't work ,it hits like in an empty void ,as soon as i unequip the mtx the skill works perfectly fine ,here's the link to the video and please fix this soon as possible ,thank you ! http://youtu.be/TKaaxxYrcnc