Hey,
If I embed a gist CSV file within a Ghost blog the search filter doesn’t work.
Search for “USB” in the original gist:
And then in the embedded version:
https://turpin.dev/bandwidth/
Fails in both Chromium 73.0.3683.75 and Firefox 60.4.0esr but there’s nothing obvious reported in the console.
Ghost-CLI version: 1.11.0
Ghost version: 2.23.3 (at ~)
I get six matches when I search in your blog post and in your Gist 
What the… which browser are you using?
Chrome Version 75.0.3770.142 (Official Build) (64-bit)
Which should be the current stable version