The camcorder discards the changes to settings, such as the date and menu items, and reverts to the factory default settings when you remove the battery or AC adapter.
The settings may revert to the factory default settings if you remove the battery or AC adapter before the camcorder is completely turned off.
Turn off the camcorder and check that the LCD and viewfinder are completely turned off before removing the battery or AC adapter.
If the camcorder is not retaining the setting following the above procedure correctly, the internal battery for the memory may be flat.
Try charging the internal battery, and contact a service representative if the problem persists.