This issue has been plaguing me as well. The suggested string will show up in the typeahead search and when I click on it, or search the full string, it will come back and say nothing is found. It basically makes Evernote useless as an actual notebook.
[Here is the search and suggestions]
[
[and what happens when I click on the suggestion]
[and here is the note that the suggestion presumably was based off of but search apparently cannot actually find]