Sooo, this guy!
My team just took him down, using only physical damage, no banshee involved (Necropolis hits him like a bullet train) for 8 million plus damage.
No rewards as usual because "we are having trouble connecting blah blah blah" which I'm beyond even caring about anymore because I now expect it to be broken and if I get rewards it's a nice surprise.
Back to Odin screen but instead of a shiny new Odin VIII to pulverize there's Mr Green again at nearly full health 5 seconds after I killed him.
This only seems to happen with the sentinel Odins others are fine.
Devs, please can you just fix this once and for all. And while you're at it maybe look at the many many threads about not receiving raid rewards after boss kills or weekly resets.