Killed the Atrocious Yeti King 3 times, no quest reward

[ThePlayMaker]

Hi, I managed to get a buddy to help me kill the yeti king.

We partied up at first, and we both damaged it and killed it, but no quest item dropped (Yeti King Memo Stone). We tried again, this time, giving me the final blow, no quest reward yet again. I tried a third time, this time without partying up. He did most of the damage and allowed me to land the final hits. Again nothing!
Now I'm stuck on the story quest, any help?

 

[Zankza]

Need screenshot please.

 

[ThePlayMaker]

I didn't screenshot at the time of the kill, so it's a bit late for that. Nothing else would really prove that I fought the boss except word of mouth and another attempt.

 

[Zankza]

Still gonna need screenshot of the quest book.

 

[ThePlayMaker]

Here is the quest book

 

[Sil3ncedShadow]

I was the one helping out and yeah we tried over 3 times and not once was the item gained. Wondering if its party related or not. item does have 100% drop rate with quest active so found it quite strange.

 

[Developer]

Must kill with player that has quest active

 

[ThePlayMaker]

Must kill with player that has quest active

Ok, but for the third try we disbanded the party and I landed the last hit on the boss. I got other loot from it, but no quest item.

 

[ThePlayMaker]

Well I finally got the quest done. I ended up soloing him (after quite a few hit and run tactics).

 

[Leba]

For future references, if someone helps you, tell them to switch character, use a ticket or not lure the boss for ~60 second, that way the aggro is "reset".