I’m afraid I can’t reproduce this issue on my installation. Could you please try to re-save the field group and test it again? If you want, you can also try to export the field group, delete it and then import it back. Please backup your site and database first before doing it.
If that doesn’t help, could you please open a new ticket and provide temporary admin credentials to your site? You can open a new ticket here: https://support.advancedcustomfields.com/new-ticket. Also, please don’t forget to explain the issue again and provide the link to this thread.
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