This issue is still there in November 2023 when Pinterest merged idea pins and standard pins into a simple pin but newly created pins are still struggling to appear in the created tab. What could be the possible reason? I am facing the same issue
The Pins created inside Pinterest or from your claimed domain will appear under the Created tab, while anything that you save with any other method (like web, or the Home feed) will go to the Saved tab.
If you want to learn more about this, I would recommend taking a look at our Help Center article.
Let me know if there’s something else I can help you with!