So i had a thread about it but i guess i find solution and here it is.We were clearing bt with dk-rogue 4-5 times now.Bu we cant managed to kill Illidari Council without bug.If you attack mage first with shiv or Tranquilizing Shot (maybe dampen magic seems enrage effect or not ) maybe spealsteal total hp pool downs %20-25 instantly.Im not 100% sure that spells make that happen but we did kill atleast 4-5 times with this way.You can find a video here (not mine) Black Temple - Illidari Council bug - YouTube