pfSense creates routing loop, freaks out, eats all WAN traffic, etc.

Hello.

pfSense occasionally blinks out and requires much attention to resuscitate. By blinks out, I mean that pfSense stays on and all of that, but just stops routing external traffic. I've checked for overlapping DHCP servers on the WAN NIC and done various other things. At first, I received errors with ping like "sendto: operation not permitted", though they'd always worked before and there wasn't any change in pfSense configuration that anyone is aware of. On reboot, pfSense generated itself a looping routing table, that pointed to itself as the default gateway. I've used Setup Wizard several times, and done other things, but they don't really seem to work. Our best hypothesis is that this is triggered by Comcast blinking on and off for just a second, but pfSense getting really confused about how to compensate for that, but that's really just a guess. I don't see anything in the logs to verify otherwise.

Please help if you can. Need things together, need that thing. Thanks.