A new custom field (i.e. not out of the box) is added to the Call_Req table and is used in a search such as a column of a list filter. The search is case sensitive. That is, if the field contains lowercase characters, only lowercase entries will be listed. The expected results and desired functionality is to return a list matching the value in the search field, regardless of case.
Check the type for the field in the database. If it is NCLOB, change it to NVARCHAR or NVARCHAR2.
You may notice that the out-of-the-box DESCRIPTION field in the Call_Req table has a type of NCLOB in the Oracle database. However, for searches based on Description, Service Desk Manager does not use the DESCRIPTION field - it uses the DESC_SEARCH field which is defined as NVARCHAR2(2000) and contains the first 2000 bytes of the ticket description.