Done Killer Joe isn't killing friendly mobs

So i tried using killer joe + draconic sword to kill sheep or iron golems, but the sword will "swing" and nothing happens.
I tested this in single player and it works perfectly there.

Is grinding friendly mobs disabled somehow ? Or what causes this

 

charge the draconic sword

 

-.- its only with friendly mobs.... im already using the killer joe for a long time, but only hostile mobs (creepers etc) seem to work

 

must be what he intended then

 

I did test it in singleplayer like i already said... (i tested it with iron golems) and it worked there...

 

not working[DOUBLEPOST=1435574703][/DOUBLEPOST]so will there be a fix if you find out why thats not working? cause i dont see any point why this shouldn't work.

Oh and Thank you in advance staff

 

thank you i will try that today

Edit: THX!! That works