We have some buttons on our website created with ACF link fields. The code looks like this: " target="">
However when translating, the button title is not available for translation when using the advance translation management. We have tested "copy" and "copy once" but not neither works. The button text remains in the primary language.
We tried the String Translation options but the button texts could not be found. We also turned on Auto register strings for translation for a while but those button text/labels were not found.
I am afraid that is expected since you are setting it to COPY, and COPY once is used if you wish to manually translate the page, without the WPML editor. Then you can manually set link text and link in 2nd language, the same way you did that in the default language.
If you are using the WPML editor, then the best would be to set the LINK field to Translate, and the URL and link text will be available for translation.