Task Manager; Tasks page "Mailbox Items" Summary Page errors

In the Task Manager, Tasks page, the "Mailbox Items" Summary Page errors with "Failed to execute Summary Page (version 2) Script 'BuiltIn.SummaryPage2_TaskManagerMailboxItems_MailboxItemSummary'." and "Script execution failed for Script 'BuiltIn.SummaryPage2_TaskManagerMailboxItems_MailboxItemSummary'. Index was outside the bounds of the array.".