Try a battery pull. Check your settings by profiles>advanced>menu>edit. When your phone does something weird like that the first thing to do is a battery pull.
Posted from my CrackBerry at wapforums.crackberry.com
It will be back...at least if you have 4.5.0.169. That's when it started happening to me. A battery pull helped, but it would randomly start happening again. Roll your OS back to 4.5.127. That is the only thing that worked....