Yes, the documentation on that field is a little confusing because it appears that the loop should not run without values. Sorry, I can’t do anything about the documentation and I don’t know if the effect that we’re seeing is expected behavior or not, if the documentation is wrong of something was overlooked when creating the new group field. The best way to get that answer would be to submit a support ticket here https://support.advancedcustomfields.com/new-ticket/
