Background of the issue:
I was trying to manage many taxonomies on my WordPress site using WPML. Everything was working correctly for months, but now suddenly, the taxonomies are not displaying as expected. You can see the issue on this page: hidden link.
Symptoms:
The taxonomies are not appearing in their respective languages as expected. Instead, they are only showing in Dutch.
Questions:
How is it possible that the taxonomies suddenly stopped displaying correctly in their respective languages?