Step 1: create a 20 character password, store it in your password manager
Step 2: the account creation process keeps the first 16 characters
Step 3: attempt to log in with the 20 character password, fail.
I found the 16 character maximum in the password rules in their FAQ, so tried the first 16 chars of my password and it worked, so the above must be how it worked
The text boxes shouldn't have a character limit on them for this very reason. If they need to configure a limit they should allow the form to be submitted but return an error telling it's too many characters. Truncating the user's input is really bad for the exact reason you mention.
There's a lot of sites with bad ways of handling credentials. I really hate sites that stop you from pasting in passwords.
I've had that happen a couple of times too. In the most striking example, I was able to log in by typing html escape tags instead of the special characters in the password. ... ... That's a very bad sign for the website security for several obvious reasons.
Walmart's internal systems used to do this, if you used a special char in your password (such as an % or &) on newer devices you couldn't log in anymore, only solution was having HR reset your login lol
None of these possibilities have any effect on their password handling security since all of that is usually handled on the frontend (on your computer).
What? No. No matter where it happens (and it could be on either side, depending on the whims of the programmers), passwords shouldn't be fiddled with this way. They should be passed through to the password hashing algorithm unchanged. There is no reason to ever fuck with them, and doing so will reduce security.
My company forces me to change the password every 3 months AND I cannot use the last 10. I use a very strong password and this rule is ridiculous. So I just change it 11 times, iterating a number at the end until I can use my last one. Fuck you.
It also normalizes resetting passwords all the time for IT. Like, the help desk can get social engineered into resetting your password for someone else. Even if you use Self-Service Password management, you'll still have callers every day who can't figure out that system.
Typically you need your main company password reasonably typeable because you'll be entering it constantly and often in places that don't support password autofill.
Which is also why forcing people to change passwords so often causes more issues than it solves. People just dumb it down until it meets the bare minimum requirements.
Speaking of corporate passwords, a shitty system has the modern windows network support modern passwords, but some important system you need reads the windows network password, but enforces ancient windows password rules, including a length limit of 16 characters