I had a similar problem with Lloyds - every time I wanted to transfer money using the mobile app, I had to type in the password manually as they had disabled the "paste" option. Given my password was auto-generated and 16 characters long - and the password field wiped every time I did an app-switch, I just gave up.
It's very disturbing to see that your worst passwords are for your bank accounts. Each bank I've worked with has some weird limitation like this. Not to forget that the only form of MFA that most banks allow is SMS - assuming they even offer MFA.
Banks are probably still running on the old mainframe (old as in upgraded in 1998 when y2k forced it), with password storage that was state of the art in 1960 (plain text, but the file is actually protected well so hackers can't get it). That isn't to say better password cannot be used, just that they have never enabled it.
I don't understand that - I get that the system that holds the data is old, but when creating an online banking system shouldn't the piece that holds the data be a good half dozen steps removed from the website and authentication?
