Repeating post is marked as such even though a Repeat post is not created for it (due to be scheduled in the past)

A Repeat post is created only if date of a Repeating post + it's schedule is in the future.

When you setup a post to be a Repeating post with a schedule such that a Repeat post date happens to be in the past (read example below), the Repeat post is not created. However, the Repeating post is marked as `Repeating`. This is confusing!

**Solution**: an error message should be displayed in such case while trying to save a post with a Repeating schedule. That post won't be saved as `Repeating` post.

Example: main post (that we're wanting to set as a Repeating post) is published on the 10th October and we're setting it to be a `Daily` Repeating post. So a daily repeat post would have been scheduled for the 11th October. However, if present time (when we're saving changes) is anything past the 11th October, say the 12th October - then Repeat post date is in the past and therefore it is not published.

L’issue ne mentionne aucun fichier ni test. Commencez par suivre le chemin de sauvegarde des Repeating posts et la logique qui calcule la date de la première Repeat post, puis reproduisez l’exemple de planification quotidienne avec la date de répétition déjà passée. C’est terminé lorsque la sauvegarde est refusée avec une erreur et que la publication n’est pas marquée comme Repeating.

Rédigé par le modèle d'indexation à partir du texte de l'issue.