iPhone iBooks search function not working

When I try and look for books in my iPhone's iBooks app's search function, it gives me trending searches but when I try and search for something, anything at all, no search results come up.

Sometimes, it takes me to this weird menu when I want to search that has a "back" option (this option takes me back to the regular search window if you're wondering what it does), a search bar, and a list of trending searches. If I try and search through that, I get suggested searches, but even if I select one of those, I get nothing but the 'trending searches' screen again.

Selecting the one of the trending searches is the only way I can get results.

I only noticed the problem today.

To cover all my bases, I've also posted under 'iBooks for iOS' here: Iphone Ibooks search not working