When a Pledge Report is scheduled with the All Open Pledges query, it does not produce the correct results. The results are different from when the report is being run manually in the database.
This may happen if you have a date in the "Calculate Payments as of" field on the report launch page. Please set up the scheduled report to instead use the option of "Use Today's Date" when doing so. You should see that the results match what you find in the database.
If your scheduled report is still providing incorrect results, please contact support and provide the Article ID for reference to your issue.