Power cycling the phone doesn't actually fix the problem for us, we have to reset the security settings.  I hope they develop a bug fix soon.  The last time this happened I asked the user if he had been driving around campus with the phone with him, ...

Having the same issue myself. When we first got the phone we were on CUCM ver 11 (the phone on 11.0(3)Sr4) when the phone would leave the range of wireless signal it would lose registration with CUCM, but when the phone was brought back in range and ...