I’m not sure if I was under siege before I logged out, but I heard steps and decided to call it a night. I logged back in to check one of my security measures, and died on login. All gear I was carrying disappeared, and was not picked up by my invader. My re-spawn location was unfortunate and I did run into the invader and die to him. I have no hurt feelings. I can not find  anywhere that says you die if you logout or back in during a siege.

Is this a bug or a feature?

I sure would not mind getting my brand new iron armor and iron sword back.