This was due to the latest change in the margin penalty calculation based on the beginning of the day span from the exchange. You can check more about this change in this link.
For example Monday you are creating a fresh position and it was carried forward. End of the day In the ledger margin will be blocked based on Monday’s beginning of the day span file.
Tuesday morning in the terminal (front end) margin will be blocked based on Tuesday’s beginning of the day span file. So only you are seeing the difference in the ledger and terminal.