My OTRS 3.0 system was set to RuntimeDB for Ticket::IndexModule. As a result, my searches on ticket number returned no results.

Is this expected?

It looks like %FieldSQLMapFullText is missing an element for ticket number.

    my %FieldSQLMapFullText = (
        From    => 'art.a_from',
        To      => 'art.a_to',
        Cc      => 'art.a_cc',
        Subject => 'art.a_subject',
        Body    => 'art.a_body',
    );

I've changed it StaticDB for now and the results are as expected.

http://doc.otrs.org/3.0/en/html/c3210.html#performance-tuning-otrs-index