@Ravlar1 @JagexOrion @JagexShauny Ok so it def comes from being in a group. Just tested it. As soon as you leave the group you're in, you can finish off the kill.
for everytime I finished off the boss. I did not want to abuse this but it took me a while before I noticed I was getting kc and loot everytime since it was piling up. I got 13 killcount and like 50 dragonstones/diamond that can be removed again (Had 5 normal trio kills earlier)
@JagexShauny During a solo ed2 I encountered a bug during the final boss fight. When I finished it off my game dc'd for a second, when it loaded again the boss would be on very low hp again. This would repeat itself over and over again giving loot and normal kc ...