Hopefully the reset password form is synced with the login form.
I emailed support to ask and they said 'oh yes, we limit the number of characters in your password'. There was no documentation or feedback on the page to tell you this if you pasted the password, but if after pasting you deleted the last character and then tried to re-type it, you would see the error. Pasting never triggered the tooltip telling you the issue.
Now I try this each time I sign up for something which is a minor hassle but still much easier than the seemingly random failures I had been seeing. It also taught me to immediately sign out and test the services' password recovery functionality to weed out the ones storing plaintext passwords, so that's good.
Funnily, the admins apparently really cared about security very much, so they required users to change passwords every few months. It was possible to change asdfghjk to asdfghjkl and keep logging in with asdfghjk. I kid you not.
They say they're working on fixing it but it's taking an awfully long time.
~10-20 failed attempts per day per IP + some rules to check for multiple IP's per account and 8 lowercase letters - most common passwords is actually reasonable.
Not if the password-hash database leaks.
Edit to add: It appears they may have fixed this misfeature. I did personally verify that you could log into their website with the phone-equivalent digits at one point, maybe a year or two ago. There's also a few forum threads about it around the net, eg https://www.bogleheads.org/forum/viewtopic.php?t=93792#p1350...
Well at least Microsoft stopped doing that and are now displaying a message that the password is too long instead of doing it silently.
I had similar issue with paypal once. Their bank account number field expected to get N digits without spaces, so it was hard limited to N characters. Of course they didn't bother telling about that. When I pasted my number with some K space separators tossed between digits, the last K digits have been silently truncated. Boom, account locked.
That happened to me on either "verified by visa" or the mastercard equivalent. I had to reset my password a few times before I figured that one out. For those that haven't used this it's an extra password protected step that comes up sometimes when purchasing things with your card.
I had it happen to me when changing a password on an Apple ID account 1-2 years ago. My password was accepted without an error and truncated to 32 characters.