Tim on Nostr: Can't speak for Nostr Vault specifically, but what you hit with White Noise is a ...

Can't speak for Nostr Vault specifically, but what you hit with White Noise is a common one. Your relay list is a single replaceable event (kind 10002), so whichever app publishes a new list last wins and the old one gets swapped out. Before trying a new client I'd jot down your relay list somewhere so you can add them back if it happens again.