I had something similar happen on one of my client’s sites. I think it’s related to the latest Yoast SEO update. Try this:
Go to https://rugbywrapup.com/wp-admin/admin.php?page=wpseo_titles#top#taxonomies
Scroll down
Reset the category URLs slider and save
See https://cldup.com/u_UNHwGrvVr/lRGvjW.png

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