When I saw it we got the buffs from the first run, zoned out, disbanded the group and reformed (before the instance reset option). Then we ran it again and went and got the buffs again. I should clarify from my earlier post, the buffs didn't "stack" per se, they were listed as separate buffs with different timers. I had the +15% hp buff with something like 1hr 10 min timer on it then another +15% hp buff with a 2hr timer on it.

Once I ported out to Org the first buffs that were at ~1hr 10 min were removed and I was left with just the most recent buffs. I don't remember exactly when this was but it was at least 3+ months ago probably more.

I got some questions regarding world buffs that I hope someone has an answer to:

Do the stamina gains from
-Hakkar buff
-Dire maul buff
-North tower buff
all stack?

and if they do stack, are the additive, or multiplicative?

Other than Zanza potions, and the Faire buff, and there any other 'special' buffs that increase stamina?

They all stack and I believe Multiplicative but not completely certain on that one.

Thanks, and I just noticed something strange as well.

My hp unbuffed is currently 6619
When I grabbed North tower buff (+5% hp) it should become 6950, which it did.
When I use Last Stand, I should go to 9035 if its multiplicative, but I gained MORE hp than that, it went to 9139hp!
When I used Lifegiving Gem (together with the above buffs) my hp became 10578. Again, I gained MORE than if it was multiplicative.

Anyone care to enlighten me? :o

0.3x0.05 = 0.015 + 1.3 = 1.315x6950 = 9139
0.15x0.05+1.15 = 1.1575x9139 = 10578

Seems like the buffs are applied sequentially with the 5% boost from the tower adding to each of them. (assuming your numbers are correct)