I hadn't realised until reading this, that I use this exact method for Best Buy.

Not intentionally though - I have my password stored in 1Password, so I know it's correct, yet every time I try to purchase something through bestbuy.com I trip some sort of ATO protection that falsely claims my password is invalid.

I'm entirely willing to believe it's something on my side (ad blocker, local DNS blacklisting, etc.) but after a certain number of occurrances, you get bored trying to debug the problem and just follow the path of least resistance.