See the attached screenshots. The test data included organizations named "Boston" and "Brno."

If an uppercase "B" is entered into the filter string, then an error is returned indicating that no matches were found.

If a lowercase "b" is entered into the filter string, then both Boston and Brno are returned.

My recommendation would be to make the filter string case-insensitive so that either "b" or "B" would result in a match for "Boston" and "Brno."