For example, post-mortem DoTs of beasts still deal 25% more damage, while these of dragonkin -- not.
Why?
It's all a matter of the buff distribution.
The buff of a beast persists through their death, while the buff of a dragonkin is triggered back and forth and can't be reapplied to a dead pet.
And as of 7.0, there might be a similar concern about the undead pets, because during their bonus rounds they deal 25% less damage.
So what does really happen here?
Let's see that log from a common fight. I was keeping applying the DoT:
TL;DR: Death of an undead pet triggers passive [Damned] that revives the target; then it applies another buff [Undead] that prevents it from death until following round, when it takes the pet to a grave.Round 15
[Lift-Off] dealt 326 damage to your [pet]Zomstrok[/pet].
Your Zomstrok died.
[Damned] healed 15 damage from your Zomstrok.
[Damned] applied [Undead] to your Zomstrok.
[[ability]Creeping Fungus[/ability]] applied [Creeping Fungus] to enemy Waterfly.
[Creeping Fungus] dealt 81 damage to enemy Waterfly.
Round 16
[Healing Stream] healed 208 damage from enemy Waterfly.
[Creeping Fungus] applied [Creeping Fungus] to enemy Waterfly.
[Creeping Fungus] dealt 81 damage to enemy Waterfly.
[Undead] fades from your Zomstrok.
[Undead] dealt 15 damage to your Zomstrok.
Your Zomstrok died.
Round 17
(skipping the details about swapping and active attacks)
[Creeping Fungus] dealt 108 damage to enemy Waterfly.
As you can see, the resurrection sickness is a part of that buff aswell -- damage after the ultimate demise isn't affected!
So no [Undead] = no nerf?
Indeed. Perhaps many of you have already used [ability]Haunt[/ability] after the prepatch -- and damage dealt is normal, because the haunting pet is technically fully dead, with buffs suspended (and haunt during the [Undead] is forbidden).
I've also checked another thing: If resurrection sickness is tied directly to the [Undead], does it mean that [pet]Ghost Maggot[/pet] + [ability]Survival[/ability] looks optimistic?
An answer is: Yes. The maggot comes back to dealing normal damage!