Summary:
The changes made to a report that was used to create a report schedule, does not reflect the same changes on the report schedule.

Cause:
When you schedule a report it will store the report settings that was set when the report was run last time before creating the scheduled report. Hence any changes made to report after creating the scheduled report will not take effect dynamically.

Resolution:
You will need to run the report once after you made the changes under settings and then schedule the report again for the changes to take effect. You can delete the old report schedule to avoid confusion.