Orfeas

Problem:
ACF custom taxonomy (i.e. using %season% as a URL tag in permalinks) slug translation not working.

Solution:
It turns out that unlike standard permalink tags (i.e. %postname%, %category%, %post_id% and etc), the %season% is a custom permalink tag. Thus it needs to be incorporate and be handled using custom code.

Unfortunately, custom coding is out of scope of this forum. However, following these examples, you can use to register your custom URL tag in WordPress and achieve the purpose. Please see the following articles:

- https://shibashake.com/wp/add-custom-taxonomy-tags-to-your-wordpress-permalinks
- https://wordpress.stackexchange.com/questions/301167/add-or-create-custom-structure-tags-to-permalink

Besides these, if you would want to extend the functionality (optional) from above mentioned articles, you can use WPML Hooks (https://wpml.org/documentation/support/wpml-coding-api/wpml-hooks-reference/).

Alternate Solution: (Shared by WPML User)
"After installing the following free version of the plugin, one is able to set the desired translations at the plugins settings and the links work properly now:
https://wordpress.org/plugins/permalink-manager/"

Relevant Documentation:
- https://shibashake.com/wp/add-custom-taxonomy-tags-to-your-wordpress-permalinks
- https://wordpress.stackexchange.com/questions/301167/add-or-create-custom-structure-tags-to-permalink
- https://wpml.org/documentation/support/wpml-coding-api/wpml-hooks-reference/