Categories Not Refreshing

Hi folks

Hope someone can help.

I am trying to update my categories, but subcategories are being erratic. I know it’s not just me being dumb, as I got what I wanted before.

Deleted some subcategories today, then made new ones. One of them, despite assigned to parent in settings, is appearing on its own in my menu on the site. Another is not appearing on the site at all (although it is fine in the actual posts).

My theme is The Erudite, and the site is https://www.exquisiteterror.com. This is driving me crazy, and has made my site look ridiculous now!