This is an obscure one, but even the tiniest of bugs in iOS 7 will eventually need ironing out. Guys over Softpedia have discovered a new Lockscreen/Passcode Lock bug.
The iOS 7 passcode lockscreen has been redesigned and simplified tenfold to be easier on the eyes. But everything you need is still there, including the small dots at the top which signal your progress as you hit each digit at a time.
Hit your first button and the first dot fills up. Hit the second digit in your code, and the second dot lights up as well, until you get all four right and the screen unlocks.
But this doesn’t happen all the time in iOS 7 Beta 4. Sometimes (admittedly not very often), the first dot will hollow out a bit, leaving just the two in the middle lit up. And, as shown in the second image to the right, all of the dots will hollow out sometimes.