Copy to locale from document not working

Describe your question/issue in detail

When using the "Copy to locale" link on a document it pops the popup, but after choosing a locale it changes to that document but doesn't copy any of the text. Works fine from the document list by using the bulk way

Could it be the case that the document you're copying to already exists in the other locale? If that’s the case, the "Copy to locale" feature will switch to that document rather than copying over the content. Sometimes this behavior is misinterpreted, as it seems like no changes are being copied.

Could you try verifying if the target document is empty in the other locale first? If it is, could you describe the steps you're taking?