check it yourself:

http://students.fct.unl.pt/~gcf17589/demo12.sdm

As you can see in the beggining of the demo both me and BloodShaman were with the bow. :o
It seems the bow got bugged when we tried to catch it and both were close to it. So i was with the bow and i wasnt able to kill with it. Also i saw BloodShaman bow shots. Only when i killed him, i was able to kill again.

there was a similar bug with some former beta version and selfhost. maybe its caused by the same issue