Running CR 13.0.27.3480 on Windows 10 X64 1909 with all the latest patches, but this one has been around for a long time.
We occasionally get an exception, it appears that there is a missing lock/semaphore statement somewhere within the "DisposeHashTableValues" function.
at CrystalDecisions.CrystalReports.Engine.ReportDocument.get_ReportClientDocument()
at CrystalDecisions.CrystalReports.Engine.ReportDocument.ClearCache(Boolean clearDocument)
at CrystalDecisions.CrystalReports.Engine.EngineObjectFactory.Dispose()
at CrystalDecisions.CrystalReports.Engine.EngineObjectFactory.DisposeHashTableValues(Hashtable table)
at System.Collections.Hashtable.HashtableEnumerator.MoveNext()
This happens when we try to do something like "area = report.ReportClientDocument.ReportDefController.ReportDefinition.DetailArea"