A unique key should be generated for a user's QR login key and their auto-login key, so the same key cannot be used interchangeably between the two.
The product uses a cryptographic key or password past its expiration date, which diminishes its safety significantly by increasing the timing window for cracking attacks against that key.
The product stores or transmits sensitive data using an encryption scheme that is theoretically sound, but is not strong enough for the level of protection required.