system
8
Whack it enough times and either you break it or you fix it!
After doing more refresh settings reinstalls (last one being the online installer ran as administrator), I finally checked the firewall settings on the gateway (the modem/router from Comcast) and changed the gateway’s IPv4 Firewall setting from “Custom” to “Typical Security (Medium)”, and that fixed the issue I was having with bugzilla.mozilla.org. (The IPv6 firewall setting on the Gateway was already “Typical Security (Medium)”.)
I also had a problem with the portal at my.chemeketa.edu, but I am not sure if the fix was adding portal.chemeketa.edu to the exception URL, or if it was by cutting back the Avast Firewall port scanning by one digit (was 1800000 milliseconds, now 180000 milliseconds, which in human terms would be changing from 30 minutes to 3 minutes), and now my.chemeketa.edu is working fine after logging in. (Edited to scratch out the exception; with port scanning cut back to 3 minutes the Chemeketa portal is working without needing an exception.)
So, for the time, I am satisfied that this problem is solved.
I still don’t know why the Firewall logs showed “System” instead of the browser (Chrome or Firefox).