What triggers this issue?
This issue reports pages that do not receive the return link from all pages specified in hreflang annotations. If page A links to page B, page B must link back to page A.
Why is it important?
If the return tag is missing, those annotations may be ignored or misinterpreted by the search engines.
How to fix it?
Review all the pages listed in this report. To fix the issue, make sure all the page versions translated or targeted to users in a certain region have the exact same set of hreflang annotations which includes URLs to all page versions. This will always provide return links between the alternate pages.