Good evening I have a two lamp fixture with a sylvania ballast in it , we installed lutron emergency ballast about six months ago. We noticed last week that when u turn off the switch one of the lamps flicker but when the switch is on everything works fine. The emergency back up works when the power is off and operates the one lamp thats flickering . Does anyone have any ideas what could be causing the lamp to flicker your help would be greatly appreciated thanks in advance