In Melbourne they said my staple from the receipt paperwork from Chile was to blame for the inability to scan. Needed override like you despite having new passport (< 4 yrs). I've used it 30 times last three months into and out of Canada (including yesterday [yyz] and today [yeg]) and never have had a problem, nor in UK, Germany, Peru, Chile, Thailand or Japan over last year. SYD in 30 days...probably get the beak there again