Settings such as the time frame are set on a tab by tab basis. So you will need to choose a time frame separately for each tab you are using e.g. Referrals, Contacts etc
Changes to the time frame will need to be re-set to ‘Defined Time Frame > 24 Hour Shift’ when no longer required or your most recently received tasks will not be displayed
From the relevant tab within Task List:
Right click on ‘Assigned Tasks‘ (towards top left)