Recently Flashed Semaphore Kernel 1.7.1 on my N4 running October 7 Carbon Nightly and everything was working fine until it disconnected from the WiFi and wouldn't reconnect. I attempted to reconnect by going into Settings and settings wouldn't open until showing a message about settings stopped working. Rebooting the device solves the issue until it disconnects again.
Steps I tried to fix it:
I factory reset and flashed the latest nightly and gApps then reflashed the HellsCore kernel.
Everything worked great until this evening the same issue occurred again, I could not access the WiFi settings after it disconnects from the Wifi even after rebooting this time it still wouldn't connect, a dirty flash of the ROM on stock kernel allows the phone to connect to wifi.