To be able to search for a string would require the ability to indicate it is a string that should be searched for rather than a set of strings with an implied "or". I do not see it has a mechanism for that. It appears to be a fairly basic search capability.
I do NOT believe that there is an implied or. I tested this behavior and it only found exact matches to the string. Perhaps you are matching part of another string in a memo, tag, or category string. It does search all parts of the transaction.
My usage and checking showed no flaws in the search function.
There is nothing in the memo fields that match. It's a flaw with search function.
@derekkent23, I actually changed the category to UofA without the spaces already. I just changed it back for demonstration purposes. Interestingly, searching for U of A returns the UofA transactions even though there is not a direct match of the string.
Playing with it some more, it looks like it's doing an AND search rather than an OR search. As I enter single letters separated by spaces in the search bar, it returns fewer and fewer matches, and the ones that are returned have all the letters in them somewhere.