Yes I once spent a whole day debugging an issue related to this because I was unaware of it. I was getting a game Steam ready and I was working on the Steam overlay that is triggered by the tab key.

QA reported that on the login screen, you sometimes had to press tab twice to get the overlay to open. Just on that one screen.

I had a piece of code that was looking for the tab keydown event to open the overlay, but in some cases the event was not being triggered. Turned out that the browser password field used EnableSecureEventInput and so the if the cursor focus was in the password input box, the tab button press would not be detected by my code. Pressing it twice worked because:

-first tab press moved cursor focus out of the password box

-second tab press was in the username input field which was not a secure input field, so my code received the tab keydown event.

The weird part about this is since the tab keydown moves the cursor focus out of the secure text box what you receive is a tab keyup event with no keydown before it.