I had a similar problem and could solve it like this:
1. Stop ALL Servers.
2. Start redis Server.
3. Start Only the Server which has crashed.
4. Wait for the server to boot up completely. (I have waited to a redis auto save/dump)
5. Start other Servers.
I was able to log in again and had no losses
If it works, please report it here again. Good luck!
EDIT:
I Think it is a sync problem, i work on a tool that makes backups sync, but on windows is it horror. ( I know we have a Linux version but this is not working!!!!!!)
NOTE: You can change your server position if you have a redis db tool. (change you "serverid") .
Not all DB changes will be upgraded,,..
MAKE A BACKUP!!