I have recorded payments for certain transactions, but the value of those payments is included in the Overdue dropdown under the Total Receivables and Total Payables sections of the dashboard. What is the reason for this?

The information displayed in the Total Receivables and Total Payables sections of the dashboard is obtained from the AR Aging Details and AP Aging Details reports. In both reports, the data displayed is as of the date when you are viewing the report. If the payment date is in the future, the payment value will be shown as overdue until that date.