I have the same issue with Undying skill - I have it equipped, I have 3 Adrinaline points active (red color) and I died a few times - all times restart, not happaned according to skill description.
Totaly broken game!
Nah, it's ok!
If I can hit 60 lvl on DM for total exploired world its ok for me!
But Devs may think to give us one more diff lelvel- Insane or something cuz there is no chalenge for a bit leveled Geralt.