EA have dropped the ball. If you logged into Madden NFL 23 during at least a 22-hour period last week, there's a good chance your Connected Franchise Mode saves have been permanently corrupted. If that wasn't galling enough, the corrupting period (from Wednesday December 28th to Thursday 29th) came immediately after EA gave people the go ahead to log in.
EA have said they expect to recover 40% of the saves, the wallies.
The issues actually began around Monday December 26th, when EA first tweeted they were "aware of players experiencing connection issues when trying to connect to CFM." On Wednesday they said "users should now be able to play CFM without issue", but no, no they could not.
Last Saturday EA confirmed they'd messed up, saying that "if you logged into Franchise leagues during this time, your data was affected due to a data storage issue that resulted in Franchise files being corrupted", and that the team were "projecting around 40% of leagues to be recovered". Their post also says you can log in safely for realsies, this time. I can't see anyone on Reddit reporting further corruptions, so you're probably fine?
The real ball-ache is that we're talking about Franchise saves, which means some people who've had multiplayer inter-Madden leagues on the go for years now have to start all over again. It's not just losing a save file, for those people - it's losing a shared piece of communal history. I'm gutted for 'em.