I thought with the 2.1 patch it was introduced that there would be temp immunity unless an action was used. This is a copy/paste of the patch notes...

The period of immobility upon being revived has been reduced, and characters are granted temporary invulnerability.

I was doing the Hydra fight last night and his one aoe attack that causes Burn was tossed on my raising self as I was being raised. It afflicted me with Burn and as soon as I ran out of the red circle it would kill me every single time. (it happened a few times).
I don't think immediately running out of the aoe zone would be considered an action as soon as you're raised does it? If not then the aoe effect should not stick on you to immediately kill you as soon as the so called invulnerability time runs out. There wasn't even time for any kind of heal or anything.