Your logic is faulty sir. The purpose of the epic quest is to obtain Zorra's HK, not the xent prototype. The mission is faulty as the loot required to complete the quest is not possible to complete at this time. Your quote states is correctly in saying "The extra part...". The issue is that this "extra part" is actually part of the mission to get
zorra's hk.
Yes, Zorra's HK is a the last part of the epic.
I tryed to said, the entire mission work. You can do the epic and claim all reward. The problem is not from the mission himself, all work.
I'm remember when we had to wait many years before claim the ZHK because the recipe didn't worked.
Now, the recipe work, the parts from Lazidol drop and that work.
Now i'll try to explain what happened from my view and my knowledge (i'm maybe wrong but it's what i think).
The old receipe needed to use the Greater Crystal to make the ZHK and it was with loot 1.0. I'm pretty sure those UL weapons was limited in quantity and that's why MA limited the quantity of Greater crystal.
1 Greater = 1 weapon
Then loot 2.0 came. Recipe has been change and now :
1 Xent Tech Prototype riffle = 1 ZHK
So i'm pretty sure, with the old recipe : 1 greater crystal destroyed by making the ZHK will mean 1 lesser and 1 weakened Crystal should go back to the loot.
And that don't work with the new recipe because no Greater Crystal are destroyed and MA failed to correct it.