Pro-652 Losing memory

As stated in the user manual, I connected the scanner to an ignition power source. It is turned on and off with the key. The problem I am having is it seems to be losing some memory. I have only noticed it on 2 different banks where I have P25 frequencies programmed. When I turn it on and try to scan the banks, it tells me nothing is enabled, but still has the frequencies in the system. I upload the programming list back to the scanner and it corrects the problem for a short time and then does it again. Any help would be appreciated.

Thanks

Pro-652 Losing memory