iPhone app pages besides home screen periodically disappear

On my iphone with iOS 16 I used to have 4 pages of apps, but now I suddenly have a single page: the home screen. If I swipe left, I immediately hit the App Search Library.

I already went through Organise the Home Screen and App Library on your iPhone – Apple Support (UK), but I have no hidden pages.

Interestingly, this happened a month or so ago (I thought removing the pages was an intended affect), but then the page with apps suddenly came back again. Now they are gone again.

I don't understand if I am casually hitting a bug (maybe correlated with os upgrade?) or just a very hidden display functionality.