Mystery solved!

Thanks for posting the logs, they definitely helped to see what the issue is. It's very simple: you have
-coin etc on your command-line (or bat file), which forces the miner to mine ETC, and this logically leads to 100% incorrect shares when trying to mine ETH. Just remove
-coin etc from your bat files (or config.txt if you are using config.txt file) and everything will be back to normal!
For everybody else with 100% incorrect shares problem - check if the miner is reporting
Mining ETC on instead of
Mining ETH on. If this is the case, find and remove the
-coin etc parameter from your bat file, or config.txt file.
I am a bit confused. In late November with the Thanos Hardfork upgrade this brought the size of the DAG well below 4 gig so that 3 and 4 Gig cards could mine again. The documentation I read said that we could use phoenix miner and use -coin ETC. I did this and successfully mind for about two months. Nanopool reflected that I was mining ETH even though I used -coin ETC flag in my config file. I never really thought about it, but now that I think about it it seems strange I mined ETC see but nanopool was reflecting ETH shares. I was thinking some sort of conversion was taking place behind the scenes. Starting last Tuesday is when all of my minors hash rates seem normal but Nanopool reflected zero shares being mine. I tried removing the -coin ETC flag with 5.4b as you suggest but my rig show no hashing. If I leave the -coin ETC flag the rig will hash but nanopool will not reflect this hashing. I did download Phoenixminer 5.4b from github that was running successfully with -coin ETC. as I remember it with the hardfork we could only mine ETC with 4 Gig cards. Isn’t this true? What changed last Tuesday to make of my rigs stop (Maybe next epoch?) And why when I remove the -coin ETC does my rig stop Hashing? Any information or advice would be appreciated.
Ken