Should be the latest version since I am on TestFlight. And I have also use the most recent Damus download from the App Store, and I get the same result
Discussion
Exactly 
Not really lol. That is a screenshot of global searching, not tagging in a note.
For some reason when searching like that it doesn’t like the @ but in notes it does 
And that is fucked up because if you do it case sensitive i.e. noB it gives you nothing. But if I type in nob then you come up. 
?cid=2154d3d7t2w582qjwyks18wfsz5cb4xlyia1vb5enepwquyp&rid=giphy.gif&ct=g
Check testflight for an update, it hasn’t been case sensitive since multiple builds ago
Latest update 
Should be 1.2.0(2) weird
?cid=2154d3d73j8hdyp4qaexcuzh0bi3q0q0z63z1xwzg9ugqoqy&rid=giphy.gif&ct=g
Not exactly what the fuck is the search input field for?