Dice has released a lot of patches for Battlefield 4 but it's still far from perfect. The latest patch released on 20 Dec brings back lag, lag spikes, frame drops and a bug that is causing crashes on the xbox 360. Dice is currently monitoring these issues to find a solution.
Battlefield 4 is so buggy right now that Dice decided to stop the development of all upcoming dlc's until Battlefield 4 is fixed. There are even rumors that EA will offer a free Battlefield 4 DLC in the future for all the problems we have been experiencing in Battlefield 4