I have also noticed this issue.
It occurs in Internet Explorer 11, Chrome and Firefox.
It occurs whether I use the numeric keypad or the keys above the qwerty keys.
I disabled the Payment & Banking Protection, but it re-enabled itself the next day!!
The errant keystrokes occur in all three cells; Access ID, Password and Security Token
This occurs with both Bendigo Bank (with Security Token) and Commonwealth Bank (without Security Token)