Personally, I have not seen this issue as I am not always online.
Try this:
Update your SW (if you have not done that yet http://us.playstation.com/support/systemupdates/ps3/)
Turn off your source of internet (Cable Modem, ATT modem, etc...)
Turn off your router (if you have additional router)
Create a new SSID (if you have the capability of creating a new dedicated SSID for your playstation. If not, no big deal)
Turn off your PS3.
Wait about a minute or so, then turn the PS3 again.
Go to setting and "Test your connection"
Once the testing is complete, open your BF4 app, and see if you are able to get into Multiplayer features.
In regards to saved data, this is what I found on the web. http://www.ign.com/articles/2014/01/21/ps4-error-corrupting-save-files. Most people thought it was BF4 causing it, but in actually, it was the Playstation. (by the way, according to reports, this is still happening after the Playstation update. I lost all my saved data (for Campaign) several times, and I have not gone back since. Having fun enjoying the Multiplayer features.
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Tried all of that (with the exception of the SSID) and it still does the same. It is definitely something to do with multiplayer mode or at least when connected to the PSN. Turn off the connection while the first menu is waiting to be loaded and then menu appears. I can go into campaign and everything OK but multiplayer asks to sign in and the same symptoms as previously reported are seen.
It is really annoying...
I also updated the console so is running with the latest release. Is there anyway to re-apply the latest patch (perhaps it was corrupted in the install)?
I don't think there is a way to reinstall the patch. I have seen many many post from PS3 players reporting (Not complaining) that they are having similar or same issue as you stated.
Have you tried contacting the EA Help at http://help.ea.com/en/battlefield/battlefield-4/? They can chat with you live or can call you back.
This might be a new bug and I am not even sure if the DEVs know about this issue. There are many many posts in BattleLog forum as well about this.
If this message helped you or direct you to the right direction, just click the XP box at the bottom right of the message.
XP = Thanks for helping or what a funny guy.
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