[paperback]

Calibre 7.26 / Linux Mint 21.

1. Open the Find bar (Ctrl + F.
2. Enter a search term.
3. Now backspace slowly through the characters.

Actual result: You may find a spurious entry in the search history looking like the bottom result in the image below.

Another thing is that, IMV, the automatic popup history is inconvenient; it should only popup if the user wants it to, i.e. by right clicking.