Toshiba keeps resetting its own clock

This is a DR570KU; bought it used a couple months ago. I usually just leave it on all the time but when you use the program timer, it turns off at the end of the time. When I turn it back on, the clock is always several hours off. Anybody ever heard of this?
Thanks

Here's the really weird thing: You have to turn it off in order for the timer to work. So it's turned off before the program and after. But it doesn't screw up the clock before the program, only after it!