AI 1 shot issue

I'm just a beginner ~30hrs playtime.

today, I was shot in the head out of nowhere today(surrounded by walls in beginner's town, no way of being sniped by mosin)
and the last glimpse from my corpse POV before respawn was an AI sitting right next to me.

the second time i return, clear out the AI in that area, but i hear an AI aggro outside the walls, i know he is approaching from the entrance, shooting him - no use, and he basically 1-shot me in the chest like my 3+ armor is nothing again.

In short, i think the current 1-shot issue is MOSTLY related to server rendering/networking-- basically what the player sees and server renders are basically disconnected, causing such a inconsistent experience about the AI difficulty.