There was a locking bug in the latest K4 Update. We have figured out what’s causing the problem and will need some time for the software engineers to resolve the issue. Here are some ways to fix it from your side before we have the official update to fix it:
1) Get the virtual keyboard on your PC, then look for the number lock button, uncheck the number lock function.
2) Connect your K4 cable to your PC, use it in the wired mode, then press the number lock key and use the number lock in the wired mode.
3) Flash the old firmware and see if your keyboard will go back to normal.