Page suddenly completely empty

[codeling]

On our page we've now had the second instance of a single page just turning completely blank as if it had no content; on the edit page in the backend, the page is also completely empty, without any controls:

We use german, so some buttons have german captions, but it should be clear what I mean: as you can see, it's missing the toolbar with "add section", "import", "export", "page templates", as well as the buttons "Add New Row", "Import" and "Page Templates below".

Don't know what's going on here, but I don't like it.

• Any ideas why the page might have gone "missing"? It is possible this happened with some Joomla Update, I didn't check the full page with every update.
• An ideas how to check whether the data is still more or less there in the database, just corrupted somehow?
• Any way to easily restore the page? The only procedure I know to be working is quite a hassle: Pull a full site backup, exported the page that is faulty, created a new one, import that page to the newly created one, re-link the menu entry to the newly created page...

Edit: This is for version 3.8.10; I didn't find an issue tracker for that version; this one here apparently is only for an outdated 1.x version...?