Outlook 2013 recall message feature working inconsistently

Using Outlook 2013 on a corporate Exchange system.  When users recall a message, it only seems to actually work for the recipients that have Outlook running.  If the computer is shut down, or being used with Outlook closed the recall doesn't happen.  When the user starts Outlook again, the recalled message is still in the inbox even though the sender recalled it hours or days before.  Our users are running Outlook 2013 in cached mode.  Multiple tests have determined that this is happening with many users.  Is this expected behavior for Outlook on an Exchange system.  Thx, J