Wanted to tell people using Rich Manalang's very useful WP-Amazon plugin that it somehow stripped out the Amazon ID I'd entered & replaced it with Rich's. I can certainly understand why Rich would use his own ID as a default in case the plugin user didn't enter any ID. BUt in my case I had my own ID entered properly & it was working properly for months. Then I noticed Rich's ID had been inserted for entries going back a few wks.
I wonder if perhaps deactivating & reactivating all plugins during WP upgrades might somehow wipe out such a setting (though I can't understand why this should happen).