Some text searches take far longer than others

(Bug, Investigate , Priority: Critical, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284oe not found, )

Summary: In the Spirit Island FAQ, some specific searches take a pathologically long time, while others are basically instantaneous. Why?

This makes no sense, but it does repro.

Test cases:

This URL runs fast: https://querki.net/u/darker/spirit-island-faq/#!Search-Results?query=%22%22vengeance%22%22
This URL runs slow: https://querki.net/u/darker/spirit-island-faq/#!Search-Results?query=%22%22defiance%22%22

What the heck is the difference?