GSEC auction credits directly happen to your demat and the depository participant (Zerodha) is not involved in this process. We’ve noticed that GSEC credits have been delayed at times after completion of our EOD processes. In such cases, we do holdings dump to Kite every morning to ensure that securities credited late in your demat account are available for sale.
When you place a GSEC order on Coin, the amount required for the transaction is blocked in your trading account which will be debited by the clearing corp (CC) on the day of settlement i.e T+2 Monday. When the money is pulled by the CC, the invoice is generated and the excess blocked amount is reversed.