I test 2 VP1420 with the same firmware version.  The first unit shows the QRcode but the second one doesn't show.

Is there any hardware difference to cause the issue?  Or how to solve the different situation?

It's related to the cookie of the browser in the PC/laptop you use.

Please clean the cookie first and close the browser.  Then open the browser to login again, you will see the parts disppeared come back.