There appears to be a bug in the Shortcodes Ultimate plugin, which affects all of the areas where I’ve used separator tabs for certain elements, notably scripts and tutorials.
It appears that since plugin’s last few updates, this has been "broken", apparently ongoing for a week.
I’ve been looking for alternatives, but none are on a par with this plugin. It’s unfortunate because I’ve been using this plugin for a long time across all of my WordPress blogs. Things break, yes, and are fixable, but I’ve always maintained "If it ain’t broken in the first place, don’t fix it!"
Hopefully, it’ll be resolved soon. If not, I’ll continue the hunt for an alternative. In the meantime, the site can still be viewed as normally as possible.