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.
I’ve had this exact same thing happen.
I’ve also had it happen where you have the two fields to verify the password is the same. One had a maxlength set in it, and the other didn’t. I was for sure entering the same password and I was so confused until I opened up the dev tools and inspected the inputs.