Yes, it happens periodically....maybe once or twice a day for me. usually doesn't last more than a few minutes, but sometimes as long as an hour or so. at least that has been my experience. if you are not already aware of it, you can connect directly to the controller in the PW via it's own wifi network. if you get in close proximity to the Powerwall you'll be able to see it as a wifi option on your phone, tablet, or PC. you connect using your system's serial # and can get realtime basic information on power flow and battery capacity through a browser. it's a nice backup for when the mobile app or connection to Tesla goes down.