Here’s my take on this.
I can see a few possibilities here, and it’s wise to consider the distinction between hidden and deleted content. The most common scenario is that the user has “archived” their posts. This feature removes them from their public feed but keeps them saved in a private section that only they can access. It’s a way to clean up a profile without permanent deletion.
On the other hand, it could be a technical issue. Sometimes the app’s infinite scroll can fail to load very old content. You might have better luck trying to view the profile on a desktop web browser. If the posts were truly deleted, they are typically gone for good from public view. A monitoring tool could be useful for saving posts as they are published, creating a record before they are archived or removed, but it wouldn’t be able to recover content that’s already gone.