Waiting for author
Overview of the issue
The Custom Post Type Permalinks plugin allows you to customize your taxonomy archive links by going to Settings → Permalinks → Use custom permalink of custom taxonomy archive. However, the links leads to a 404 error for archives in secondary languages.
We can’t provide a workaround at the moment, but we have been in contact with the author as some changes should be applied on the plugin.
Next steps to resolve this issue
This issue was last raised with the author on GitHub: https://github.com/torounit/custom-post-type-permalinks/issues/106.
Please feel free to submit another issue to the author to help move this along and find a resolution.