Nostradamus on Nostr: Sometimes the list returns and sometimes I have a different list because I started a ...

Sometimes the list returns and sometimes I have a different list because I started a new one after losing the first list. Also sometimes I have a list that looks like a combination of both lists merged.

Are the lists stored locally or on a relay server? If a relay is down at times would this cause a list to disappear, and then I started a list stored on another relay, and when both relays are active I get the merged list? Just brainstorming because I'm not sure how they are stored.