I notice on rare occasions when I hit the unlock slider it doesn't always register or slide all the way. I have to slide it again. I never had this pre 4.3 and it doesn't happen to often.
Since 4.3 isn't officially out - and presumably only developers are supposed to be using it - are you sure you're using the GM version or an older build.
Im going to do a restore to see if that clears it up. If not I will do a restore when it is released on Friday. Unfortunatly I have to restore my backup as I have so many settings I do not want to have to do over not to mention having to start from the beginning in all the games etc.