Search not displaying all results

I have enabled enhanced user interface, which activated a search box.
When I search on a specific string, it only shows me results where the string is at the beginning and not when the string is part of a larger string.
Let me give you an example:

When I search for the word “filet”,
it would return:
– chicken filet
– filetchicken

but it would not return:
– chickenfilet

Hope you understand what I mean, it is not looking for strings inside strings, it only looks at the beginning of a string. Is this something I can enable?