By default Workload Automation AE keeps 7 days of historical records in the AE database. After that time the records are archived into flat files. Once they have been removed from the database those runs/details would not be available via autorep.
WCC keeps 30 days of historical records in the WCC database. After that time the records are removed from the database those runs/details would not be available via WCC.
Additional note - If a job fails to enter a true running state no "job_run" is created in the AE database table ujo_job_runs. As a result, one will not see that attempt of a run via WCC or autorep. Examples of situations like that include: inaccurate job owner details, inaccessible std*files.