There’s a number of issues with Cobalt Ooze and Mana Voids in certain dungeons/bosses during Twilight Protocols.
When some bosses go immune (such as Earthrager Ptah, Vanessa VanCleef, Admiral Ripsnarl) and become untargetable/phased, slimes will still spawn and activate their abilities. But the slimes are untargatable so it can’t be played around.
So what will happen is, the boss will disappear for their transition/adds phase, then randomly the slime mechanics will occur, such as a Mana Void or Faceless Ones spawning out of thin air.
This has a double whammy effect with the next bug; The Mana Void is not always returning mana when killed. I’m not sure if this is due to killing it too quickly but if a Cobalt Ooze gets through in favor of killing the Dark Ooze, then our mana users are quite often left in the lurch for the entire fight almost.
Conversely, this means we’re forced to let the Dark Ooze in which results in the Faceless Adds which can overwhelm inexperienced/lower ilvl healers in pug situations.