"quitter ce tutoriel" isn't always clickable

[glef1]

When one clicks on the Help button (with the question mark "?"), click on "suite" several times until the end of the tutorial (see screenshot 1) and comes back one step (by clicking on "retour" one time), the "quitter ce tutoriel" button isn't clickable at all (second screenshot 2).

Example: https://www.lafabriquedelaloi.fr/articles.html?loi=pjl09-556

Screenshot 1

Screenshot 2