Suggestions :
When we enter a cheque payment with future cheque date it is treated as PDC. A PDC Received transaction record is created for the received against the Sales invoice number and its reference and the PDC cheque status will be In-Progress.
The invoice will be adjusted only when we clear or complete PDC receipt to receive and that happens in PDC Received to Receipt process. However, remarks field is not mandatory in PDC Received transaction record. But if the remarks is entered then it should be referring logically to the transactions and not to be only special characters.