i'm not sure about that, i had this feeling in fallout 3 as well, but the enemies seem to get stronger after you die.

let's say you are fighting 4 enemies, you manage to kill 3 of them then save and after a fight the last enemy kills you.
?You load your save, and from then he manages to one shot you the second he sees you.

Each time you load your game, this enemy is there, stronger than ever, and he destroys you.

And you know that in others circumstances, he won't be so precise in his shots.

My explanation is that a kind of "max damage" state is applied to this enemy at one point, and it follows him even if you load a save.

I'm quite sure if i play now this saved game, the enemy will be as i first fought him; strong but not to that extent.

I noticed that sometime having been killed by a mine, the last saved game automatically loads and the mine isn't here anymore.
?This shows that the state of the game isn't exactly the same when you load it, so... maybe this isn't just a feeling ?

I've noticed something similar, but I'm far more willing to chalk it up to the game's AI beginning before you have full control of your character after loading the save - this will give the AI plenty of time to line up a perfect shot and catch you "unawares" as far as the game is concerned (meaning taking a hit outside of combat - as denoted by the music), which can deal additional damage.

Thanks for your reply

I'm happy to see that i'm not the only one having noticed that, and your explanation seems plausible.