Books removed themselves from their categories

Nearly all of my books removed themselves from every category except for "Your Library"* sometime in the past 20 minutes or so. I only noticed because I was adding new books.

I mean, I _was_ going to reorganize them anyway, but...

* Actually, I see that "To Read" was mostly unaffected too. Maybe it only affected the categories I made?

Edit: I'm looking from my Profile page, so I don't _think_ it's a case of "viewing only books that share a category with the one I have unknowingly selected" :ohdear:

Back to normal? It looks like it had caught up (probably was a caching issue), but let me know if something's still looking weird.

Caching sounds likely... I think one of my categories is back to normal.

I'm feeling suspicious of another, but on the other hand I can't remember what it was to begin with. >_> Oh well!

I'll call it fixed and see if it happens again. Thanks!