Or worse, they truncate your password after you've already used it for years and years.
I had a 30-character password with Bank of America. Somewhere along the line, it changed its password requirements to only allow a maximum of 20 or 25 characters (I forget), which automatically invalidated my password.
The password was stored in my password manager, so I knew I wasn't entering it wrong.
BoA support said I should use the "change password" feature to update my password, but I couldn't because it requires me to enter the old password, which it would not accept. For some reason I can't remember, I couldn't use the "forgot password" feature. Maybe it also didn't work right.
I spent an entire day on the phone getting bounced from person to person before finally someone was able to take a new password over the phone.
Since Bank of America can't figure out how to build a web site login, I no longer trust it with my money. I emptied that savings account and paid off the credit card as quickly as I could. I no longer use BoA.