For some reason, it is rebooting every 4 hours literally to the minute.

I did notice it reboot occasionally with the new firmware (not so much with the old one), but when I looked at my connection log I realized it was at exactly 4 hour intervals.
The configuration is basically stock using PPPoE, WPA and I have one time based internet restriction by MAC address.
I checked the logs but since it is a hard reboot there is no indication about why it had rebooted (just the normal reboot kernel messages and PPPoE etc).
I plan on examining the cron configuration to see if there is something at 4h intervals tonight, but has anyone else noticed this?