Unkillable Mobs/unable to complete bounty requirements

There are 3 instances so far this season that I have encountered mob that will not die preventing progress of Bounties
This season I am playing a wizard using the typhoons veil set and Various mobs are immune/unkillable.
The second Demonic Hell Bearer in Act 3 on Rakkis Crossing (bridge) just before you head under it takes little to no damage, never dies, and continues to vomit mobs.
In the Caverns of Frost L2 mobs there (Wintersbane Huntress) did not die after having it’s health reduced to 0 and it stopped attacking. This did not count as being dead and was part of a kill everything in that area bounty. The bounty was not completable because of this. No one in the party could damage it.

Also, The last is Shaitan the Broodmother, Desolate sands, Act 2, I took her health down to 50% and then she would not take damage from any of my abilities. She then killed me three times as she was still active. Arcane torrent, Hydras and black hole made no damage after the initial damage done. A barbarian then managed to kill her. Lucky as the bounty required us to kill the mobs in the cave she creates when she dies.

Are there any other instances people are encountering of this? And if they can they be fixed that would be awesome.

This is one of the most frequently reported issues on the Bug Report forum and every time we direct people to the stickied Known Issues thread at the top of the forum…