Edit:
https://forums.elderscrollsonline.com/en/discussion/comment/3422135/#Comment_3422135
These are the four bosses (sorc, NB, tank, healer) just before Lord Warden. Each one has 4 million or more health. Definitely wasn't this high before the patch and it seems weird that just one of these guys has more HP than the other bosses.
Edit: Here are the post-patch health values of the bosse:
Lord Warden's Knight: 3,740,235
Lord Warden's Templar: 4,462,035
Lord Warden's Berserker: 3,740,235
Lord Warden's Necromancer: 4,462,035
Edited by bottleofsyrup on October 6, 2016 6:56PM