I've scoured all of our logs for lists.sonic.net - I only see an admin login from your IP address on November 2nd - no other attempts were made to change settings. As far as I'm aware, there is no timeout to the flag.
While using the 'Emergency Moderation' setting is one way of forcing all posts to be approved/denied by a moderator/administrator, I recommend taking a look at the Sender filters
section of the Mailman documentation (this refers to the Privacy Options --> Sender Filters section of the admin page) - it looks like you already have posts to be moderated by default, so the Emergency Moderation setting isn't needed. (The reason it exists is to force all posts to be held for moderation either when you have an open discussion list or a partially moderated one.)
-- Joe M.
Sonic System Operations