Yes it has outbox implemented, what signer are you using with nosotros? I recommend using a browser extension like nos2x and check all the messages the client is trying to sign in the popup (don't click "authorize kind 10002 forever"), if you are using a mobile client like damus/primal/amethyst and put your nsec on it, you have no control on what the client is signing (and possibly overwriting it), use a remove signer on mobile like amber.
Did your list was overwritten when you trying to change your relay setting or when you just tried to access some client? you will need to hunt down the client doing that.