Error Handling fails: IF NOT CODEUNIT.RUN() THEN...

Got codeunit 50000. Call it from a form at the moment before enabling the entry on the Job Queue to process from NAS.
It calls itself in order catch the exception and update the ParamEntry record.

Report::50000 populates a test table with 10 records.

Second time the codeunit is run, it tries to populate the table with the same records thus causing a "the record already exists" error.
But instead of the system executing the code after IF NOT CODEUNIT.RUN(CODEUNIT::"50000", Rec) THEN BEGIN, it just breaks and doesn't update the status field to Failed. If I put an ERROR('My error message') in Report:50000 it does catch and handle the error.

Any reason why "the record already exists" would cause the error handling to fail?

OnRun(VAR Rec : Record "Job Queue Entry")
--------------------------------------------
GetParamEntry();

IF "Parameter String" <> '' THEN BEGIN 
  "Parameter String" := '';

  IF NOT CODEUNIT.RUN(CODEUNIT::"50000", Rec) THEN BEGIN
    ParamEntry.Status := ParamEntry.Status::Failed;
    ParamEntry.MODIFY;    
    COMMIT;
    ERROR(GETLASTERRORTEXT);
  END;

  ParamEntry.Status := ParamEntry.Status::Completed;
  ParamEntry.MODIFY;  
END ELSE
  Code();

Code()
--------------------------------------------
REPORT.RUN(REPORT::"50000", FALSE, FALSE);