Welcome to the forum.
Not a dev just a user. I used a "clean" version of 1.0.193 portable on Windows 10. I deleted the default notebook then created NB, then SB1 in it then SB2 in that. In SB2 I created a note called "Search Test" containing just the word "Antidisestablishmentarianism". I then moved to the empty NB notebook and used the search bar to search for "Antidisestablishmentarianism". Like for to you, nothing happened. I navigated back to the note and then back to NB. From that point onwards the search did work. Also despite deleting the NB notebook and starting over again it continued to work. So it isn't the word length! Is this search still failing on your setup?
I also tried with the pre-release verion (1.0.194) and I couldn't get the search to fail at all.
Finally, if you do ever need to ask for a bit of help on the forum, letting people know what Joplin version and OS you are using can be quite helpful... 