@AnnetteT correct. Factory reset doesn't take it to version it came with. You have to downgrade the version to fix this issue. I did it just after posting the issue here and it worked fine. Process...

Router had been working with no issues for months. On Friday, 17-Novembet morning it automatically upgrades the firmware to version 1.2.5 Build 20231025 rel.50143. Since then, it has tons of issues....