UPDATE: This was fixed in the 4.3 update that came out for my phone lately. No need to think about it anymore, also I can't give any further details.
I have a quite new Samsung Galaxy S3 4G (GT-I9305). It is running an unmodified & unrooted version of Android 4.1.2. It works mostly perfectly fine, but there is a slight problem with NFC.
I have edited the buttons visible in the notification center. I have added the NFC switch to the buttons. My problem is, the button is not working. It is disabled, and has no green/gray indicator.
However, when I tap the S Beam button S Beam and NFC get enabled.
After this, if I tap NFC with S Beam either enabled or disabled,
System UI crashes. When the UI reappears the buttons are as before tapping NFC, but now I can successfully turn off NFC, and also turn it on and off again. Restarting the phone brings the problem back again.
Another way to get NFC turned on while the button is disabled is to go to Settings > More Settings and turn NFC on. This also turns NFC on in the notification center, but again, trying to turn it off causes
System UI to crash.
What could be causing this behavior?