In password security, the longer the better. With a password manager, using more than 24 characters is simple. Unless, of course, the secure password is not accepted due to its length. (In this case, through STOVE.)
Possibly indicating cleartext storage of a limited field (which is an absolute no-go), or suboptimal or lacking security practices.
How do you know when a password is leaked?
What’s the distribution of variance in brute force protections on online services?
Why would it matter? If they can access the password they probably can access everything else on that service. Just don’t reuse passwords.