Hi Gareth, Mary,
I created this tracker issue: https://tracker.moodle.org/browse/MDL-57553
First time I noticed this, was with the %add=assign% downloadable json-file from Moodle.net. I then rebuilt the tour for Dutch in our Moodle, and noticed the issue when using any of the .id_ CSS selectors used to identify the various fields in the form. E.g. [aria-controls="id_general"] or [aria-controls="id_availability"], but also applies to all other steps associated with CSS selectors that have style attributes (font size, color, etc.)