Visiblement ils ne regardent pas les critiques et ne corrigent pas leur extension depuis 3 ans : https://addons.mozilla.org/fr/firefox/addon/wayback-machine_new/reviews/?score=1

Comme dit plus bas : I love the internet archive and the wayback machine, but I had to disable this extension because it constantly gives me false positives and won't let me see pages that are live. At the very least it needs a button to "Show Live Page" so I can override it. But as of now it's impossible to override without disabling the extension entirely.