Just search "code" in the chat search. You will immediately that this will show up, but hey, where does it says "code" in that string? Well, apparently you are searching the HTML version of the string, to be more accurate:
<code>!.is()</code> != <code>.not()</code>
This is unexpected, and sometimes screws what you expect to show up wasting your time. Can the search be changed so it ignores the rendered html and search based on the markdown version of the message?