Firstly, check the references of this page from the References tab in the left hand side. Check if everything looks okay there.
Secondly, enable a debug log on "com.adobe.cq.xf.impl.ExperienceFragmentsReferenceProvider" and replicate the page again. You should see messages like "Determining references to experience fragments for resource at", "Adding the parent experience fragments as references" etc.
Hopefully, these messages provide more info to understand the cause.