Since I have reached level 60, I started farming act 1 Inferno to get some gear.
My usual farm routine is to get five stacks of Nephalem Valor as quick as possible, and then kill elite / champion packs and finish with Warden & Butcher.
When getting my five stacks of Nephalem, I noticed that, occasionnaly, some packs give me a double stack of Nephalem Valor. Why is it so ?
If there is a specific way to get double stacks on pack, this could make farming a bit quicker 🙂
As suggested in this post, there currently seems to be a bug when killing several monsters of the same pack at the same time.
What happens is that the last two monsters of the champion pack dies at the exact same time, triggering the Nephalem Valor stack ‘gain’ twice.
The above post seems to point that killing more monsters of an champion pack could give you more stacks of the buff.
Note that this can only happen on champion packs, not rare mobs, as only champion packs allow different monsters to trigger the Nephalem Valor ‘gain’.
Even if the post has no answers from Blizzard, I guess this will be considered as a bug and fixed somewhere in the future.
Edit : The bug has been fixed with a hotfix on July, 3rd 2012.