I purchased a package with 2 V2045-60 digital timers last year and this Christmas season both begin to stop working after a few hours in service. The problem is that when you set the time for a 8 hours it shuts off only after a few hours. I tried changing the duration time to 6 hours and the same thing happens. I am only using the photocell times for one string of lights. Both timers are failing, is this something that happens after a year.functioning