Weird X250.8 Meter Behavior

I just recently noticed a strange behavior on my X250.8 meter. With no input the meter has a small rhythmic "twitch". It literally looks like my amp has a beating heart. In the past the meter has only shown movement when pushing the amp from class A to AB. Does anyone know if this is cause for concern... as I said there is NO input and the wall voltage is a constant 120.6 volts.
Thanks,
Tom