Can you please let me know which fields stopped working? And where are those set (in which field group) and where are they displayed (on which page, post, or custom post type)?
You mentioned that they "stop" working. Since when? Can you relate it to any change (update, migration, edit)?
I want to request temporary access (wp-admin and FTP) to your site to take a better look at the issue.
It would be better to use a testing site where the issue is replicated.
The information you will enter is private, which means only you and I can see and have access to it.
Maybe I'll need to replicate your site locally. For this, I'll need to temporarily install a plugin called “Duplicator” or "All in One WP Migration" on your site.
This will allow me to create a copy of your site and your content.
Once the problem is resolved, I will delete the local site.
**IMPORTANT**
- Please make a backup of site files and database before providing us access.
- If you do not see the wp-admin/FTP fields this means your post & website login details will be made PUBLIC. DO NOT post your website details unless you see the required wp-admin/FTP fields.
The choice between Expert and "Same fields across languages" really comes down to the end goal, if you are simply planning on use these fields as they are in the translations and not having a more complex set up this is ("Same fields across languages") typically the way to go.
Regarding the other issue -- I can see what happened here.
When the ACF Field Groups were set to "translatable", you are essentially able to add a "translation" for each language, the moment they were switched to "not translatable" this was removed and the translations are now showing in the same screen as the default language.
Same behavior would happen if you were to remove WPML without clearing the data, you would see the pages listed twice for example. Homepage Homepage-EN
With that being said my recommendation is to do the following:
I've set the translation to "Same fields across languages".
I've tried moving the Welsh fields from the English and English to Welsh, for example moving area_cym field to the English field group. It says it has moved but when i visit the field group again, the field is still there and hasn't moved.
