Tell HN: Submitting an empty login form at Signature Bank NY logs me in?

With all the news regarding Signature Bank NY's shutdown, I decided to visit their website. Their login form was front and center and for no particular reason I submitted it without entering anything. I was surprised to see that it appears to have actually semi-logged me into someone's account, stopped only by the 2FA setup... [0] What the?

As the FDIC is now in control of the bank, I reported the finding to them.

[0] https://www.dropbox.com/s/9ew07fifrfgxmyu/signaturebankny.mov?dl=0