I have a 5th Gen AirPort Extreme running 7.6.1 and every few days it just reboots. I have it poited to a syslog server to see the messages, but there is nothing, it just reboots and comes backup as normal. This even happens when I`m not home, I know it does that as I get alerts from my monitoring system.... I do have a USB drive connected to it for my TM backups.. Any one else seen this ?