Ahh that explains the intermittent error. Glad i could help somewhat, lol.
I started my vanilla test server with your params and i GOT the error. I then stopped and started the server and the error went away. I deleted the server identity "RustLevels" and started the server, error still not there. I then reinstalled my vanilla test server and tried...
I assume that you moved to a windows VPS? Can you please post your startup params with your +server.hostname and +server.identity. Maybe you are using characters that confuses windows like the "/" in "11/16"
Good, I was testing you. Seems like you know what you are doing. good luck.
EDITED AWAY. Was stupid