Yup that's what I was using, and getting at least 5 reboots a day. Tried wiping/restoring several times. Finally read on here about people having problems with adguard dns setting, so I removed it and the reboots went away.
My wife's phone has the same problem as op's. I called at&t and they're sending out another i777. It'll be here in a couple of days.
Mine is still working just fine.