最近的一个判决给我们解决了这个问题，Brown v Minister for Home Affairs [2018] FCA 1722http://www.judgments.fedcourt.gov.au/judgments/Judgments/fca/single/2018/2018fca1722 的第23 段
para 23 Therefore, if a delegate was to exercise the power by cancelling a visa it may result in a determination by a Tribunal (after a formal hearing with all the attributes provided for by theAdministrative Appeals Tribunal Act 1975 (Cth). It is unlikely that a determination as to whether to exercise a power that is entrusted to a repository of that kind (to be exercised in the manner provided for in that Act) could thereafter be re-exercised on the same facts in a manner contrary to the determination made by the Tribunal.
如果AAT 做出了推翻移民决定的判决，移民局是不能依据同样的过错来再次取消签证的。这就是为什么有些利用移民局程序失误拿回来的签证， 移民局没有第二次机会弥补程序上的过失，客户的签证可以永远保住的原因。