Dec 31 20:00:14 WAN Connection: ISP's DHCP did not function properly.
Have you tried resetting 'DHCP query frequency' from Aggressive Mode to Normal Mode?
I see this in my logs too but I do not have a rebooting issue. I am using Boot Loader 1.6 and I am in Sunnyvale (near San Jose, CA) on Comcast using a Motorola SB6141 modem. I left my DHCP query frequency on Aggressive Mode. Merlin's 374.41 of course.
For the record I also have hardware acceleration and uPNP on. Nothing plugged into the USB ports and no samba or DLNA shares configured.
For what this comparison is worth.
I hope you figure it out.