My character can't die in Fallout 4 for the Xbox One. When my health reaches zero, the screen flashes and I'm suddenly back up to full health.
Third person view shows me as being knocked out on the floor, then coming to rest in a sitting position, just like a humaniod companion does when they lose all their health. After a second or two, my character rises up like nothing happened, again, just like the companions do after combat.

...I beat SWAN the Super Mutant Behemoth with nothing but a sword, and this startling newfound ability to defy death, and Swanzy's boot.

If anyone else has this problem (is "problem" the right word?), feel free to speak up. I'll post this in other sections too. Who knows, maybe bethesda knows about this glitch.

I'm experiencing this problem on PS4. By chance did it start happening after you started the mission "Confidence Man?" That's what triggered it for me. I don't know about you, but I also can't kill named NPCs except for Raider and Super Mutant Bosses.

I havent triend killing named NPCs yet, but I'm halfway through the "Confidence" quest. I really saw this issue for the first time when I was on the mission to hunt down the scarred man who stole Shaun.

This glitch also happened while another problem was acting up, in which I could not leave sneak mode, but could still sprint and jump. It was odd.

Y'know, some people would kill to be able to avoid death. ...kind of an odd sentence, but I'm not one of them. I might just reload the most recent saves whenever i get knocked out.That was I can sort of get around this issue.

An "I Refuse To Be Jesus" fix, if you will.
..although I might go on one more sword rampage before then.

Well that's depressing. Two different platforms, means we probably can't do anything about it. I guess until Bethesda gets in touch with me or you I'll just have to start a new character and avoid that quest for now X3 Hopefully if and when it gets patched, I'll be able to pick up where I left off.

I couldn't bear to start a new character. And I don't think Bethesda is going to patch this particular problem for a while. Just load the Honesty "patch", reload whenever you would normally die, and go kick some wasteland ass.

I don't know about you, but I actually can't complete a good chunk of missions because certain NPCs are invincible. I'd like to just do the 'reload on death' diy patch, but that won't exactly cut it for me.