I already posted this on wow-eu forums, but like usual very little response.

However what I found out (been testing this on nightmare vines) is the following:

Improved defensive stance is bugged atm. It normally decreases magic dmg by an aditional 6% while in defensive stance.

However there is a bug. If you get a dot while in defensive stance it gets aplied and actually stays on after you swap out of def stance.

However if you get dotted in battlestance or zerker stance and then swap to def stance the only difference is the normal -10% dmg modifier from def stance and not the extra 6% from imp def stance.

So basically the talent doesnt work if the dots land on you outside of def stance.

In other words, the 6% extra spell dmg reduction only gets aplied if you are in def stance when the spell lands on you.

Can anyone else verify this?

Not really a bug it is how DoTs work now. They take account for all modifiers at the time the spell is cast. This is then how much damage the spell will do over the course of it's duration. This was changed about a year ago.

This would seem like it would be working as intended. The damage is determined at the moment the spell lands, much as DoT spells cast during a trinketed +dmg activation retain their damage values after the trinket fades.

I would be curious how an ability such as shield wall functions with a DoT on though.

er... he's saying that it does get modified by berserker/defensive stance after it is cast. Its just that defensive stance reduces it by 10% instead of 16%.

DoTs take into account your spell damage at the cast time, not all modifiers.

Edit: Shield wall does what shield wall says it will, 75% less damage taken.

I noticed this with nightmare vine, while farming. I dont believe its related too imp defensive stance though, since i had the same happen the other day with as another spec without that specific talent.

Here is the debuff we're talking about http://www.thottbot.com/s28721

When I get the debuff in battle stance it ticks for 100, and 110 in beserker stance, which is normal, after getting the debuff in those stances and then switching too defensive stance it ticks for 90, as expected. But if i get the debuff applied in defensive stance it ticks for 81. This both works for imp defensive stance and without.

I'll guess I'll start checking it with a red or rip or so as well then, and with a lock dotting me up, thansk for the feedback.