So I did my 2nd and 3rd toon's runs tonight.
3rd toon was an all-alt run, so we didnt do the new bosses (we dont delude ourselves, theyre not geared enough).
2nd toon run proved to be very interresting indeed. Festergut was a puzzle to be sure:
Tanks at first was Pally and DK.
DK got instagibbed within 3-6 seconds from taking over the boss.
Pally just kept going and going untill he exploded from 10 stacks of the debuff.
As an experiment, we decided to start swopping out healers, even borrowing one supergeared shammy alt of a friend to come in and replace paladin healer. Same problems.
Switched other healer (priest) back in to replace the paladin healer, so we get a mix of it and see.
Same results.
Switched back to original layout healers, as we now conclude the heals is not the problem.
Switched DK for a warrior.
Now the paladin got instagibbed!
Warrior this time just kept going and going untill boom.
Switched the Paladin back to the DK.
Encounter cleared without so much as a hint of difficulty.
We will definitely be looking into this very strange situation more in detail.
How can the same tank get instagibbed when standing next to certain other tanks, but not when next to others?
Puzzling querum indeed...