Wild Bill 888 wrote:
“ fwiw the anode rod never did degrade over time“
Is it possible that the rod is not grounded (eg. threads wrapped in Teflon tape)? No current flow, no protection.
Scrap off a few flakes and touch with a flame. Burns white hot, mag, melts, aluminum.
Teflon tape isolating an electrical connection btwn the water heater tank threads and the anode rod plug threads is a fallacy. An urban legend. An internet creation.
Teflon tape crushes btwn the male and female threads to fill the voids and imperfectionsin order to keep liquids from leaking through the threads. That's why it comes out in fine pieces and why some of it comes out in strings when removing it and cleaning it from the threads when the plug is removed.
The tape is basically destroyed as the anode rod is screwed in and tightened resulting in plenty of metal to metal contact. Believe it or not metal can penetrate plastic under Force.
If Teflon tape were so good at isolating the "electrical connection" btwn the tank and anode rod, the Teflon tape would be 100% intact and still look like a flat piece of tape when the anode rod is removed.