Currently, the constraint will reject any password found at least once on pwnedpasswords.com. While this is indeed the safest behavior (and so a sensible default), it means blocking half a billion passwords currently.
The blog post announcing the launch of the v2 (which is used here) recognizes this usability nightmare, and explains that this is the reason why a count is provided for each password: https://www.troyhunt.com/ive-just-launched-pwned-passwords-version-2/#eachpasswordnowhasacountnexttoit

I would be great to allow configuring the threshold at which passwords should be blocked (the existing behavior corresponds to threshold=1)