A player mentioned that he died several times losing his kit when just sleeping.
Seemed to him like a self kill.
Weird thing is that the same happened to me this morning for the first time.
I even still was in vanished mode but died to...nothing.
What is this and how can this suddenly happen? Any ideas?

I have also recently experienced this but usually when my base is in a cold biome and i have a rad suit on, As I usually build on icebergs or in caves in cold biomes i used to wake up and then suffer loss of health (slowly) due to cold but now die (while sleeping) in the same circumstances.

This is a really old Rust bug I guess.
I remember noticing this over and over in the last 4 years.
Sometimes I wished Facepunch would stop putting content in the game and
would spend 3 months on fixes and performance issues.

also backpack pro can kill you when sleeping.

I don't use that.