Password Reuse -- Website Generated Duplicates

[jmhbpc]

Not sure if I should add my query to this thread

Password reuse - interesting edge case

We all know that using a single password on multiple web sites is a bad idea, due to password-stuffing attacks (where an attacker uses a password stolen from one site to try and access another). But here’s an interesting edge case. Several years, two financial institutions I do business with merged. I have a separate login (and password) on each company’s web site, but my accounts are linked together. When I log in to either site, I can view information about accounts stored on the other. A…

So I’ll start it, first, as a separate thread

I have a login to a website for which the website itself, it appears, has generated a couple of duplications. I think it is generated by/or sent to a Microsoft Authorization system called b2clogin.
Compromised-Password Detection logs these duplications as reuse