Unable to compare two string values in a customised report

I would be grateful if anyone can tell me why the code is not working as it should

I have the following code:

$set $$ExtRef Empty

$repeatAllIssuesSortExternalReference where  AppliesTo = ‘’           <- this just gets issues in Test Scenarios

$if $$ExtRef <> $ExternalReference               <- I have also tried $if not $$ExtRef like $ExternalReference  

$Description              

$set $$ExtRef $ExternalReference

$endif

$ExternalReference                                                                                                                  

$endrepeatAllIssues

The output I get is in the attached file. 15972 http://........    is the external reference for the issues.

There may be serveral test scenaios for a given issue.

I am trying to list test scenarios by issues - which I am getting.

As the list is sorted by external reference, I only want the issues description to appear once for each group of test scenarios.

Issues 1, Issues 2 etc ate the issues description. So the required output would be as below.

In the actual report I will not be displaying the external reference but $ParentName, ie the test scenario name. The external reference is only displayed now for debugging.