7 years later, but i've a 0.4 server and had this same issue XD
at
bool Player:
nKilledCreature(Creature* target, DeathEntry& entry)
this code:
if (!Creature:

nKilledCreature(target, entry))
return false;
that triggers the creatureEvent function, was called before the entry was setted to unjustified. So you just move it near to the end of the function, before:
if(entry.isUnjustified())
Greetings!