Battlefield 4 Beta Patch Fix Emerges
The latest patch changed directory, not controls in Battlefield 4's beta.
Some players have reported problems with the latest patch for the Battlefield 4 beta which changed the game's directory but did not actually affect any controls according to Reddit.
The patch altered the directory from 'Battlefield 4' to 'Battlefield 4 beta'. If you've been affected, all you need to do is move PROFSAVE_profile and PROFSAVE from C:\Users\YOUR-WINDOWS-USERNAME\Documents\Battlefield 4\settings to C:\Users\YOUR-WINDOWS-USERNAME\Documents\Battlefield 4 Beta\settings.
You'll need to load the game once for the folder to be created.
Apparently the reason DICE did this is that the old configuration file with the keybindings had a 'memory leak' where the spectator controls would take up more and more space for every key you changed until it crashed the game for some players.
The process listed above does corrupt some saves it seems which means that if you're affected you'll need to set everything up again unfortunately but that should only take a few minutes.
Battlefield 4 is set for release on October 29th in North America and November 1st in Europe on PC, PS3, and Xbox 360. It will be a PS4 and Xbox One launch title.