The following screenshot illustrates the configuration under Maintain Dunning Procedure: Special G/L indicator.

Considering Special G/L Transactions in Dunning
For every dunning procedure, you specify which transactions are to be included in the dunning run. A distinction is made between standard transactions and special G/L transactions.
Special G/L transactions are transactions that must be displayed in a particular way in the system either for reporting purposes (balance sheet) or for other reasons internal to the company. A quick reminder here that down payments, bills of exchange, and guarantees are all types of special G/L transaction in SAP S/4HANA Cloud. When you maintain the dunning procedure, the system offers a list of special G/L transactions for selection. Here, you can configure the transactions to be considered for dunning.