This issue is typically caused by using an incorrect source field in the merge mapping rather than a problem with the merge functionality itself.
If the merge template is mapped to the Opportunity Name field, the output will display the full Opportunity Name, which may include additional information such as the donation amount, date, and campaign. To display only the donor's name, use the Account Name (or the appropriate donor name field) from the report instead.
If a donor's first name is not appearing in the merged output (for example, in a salutation), first verify that:
The report contains the expected donor name data.
The merge template is mapped to the correct field.
The merge action is using the intended report and template.
If the template and merge action work correctly during testing but the issue persists in a specific merge, review the merge action configuration and field mappings to identify any discrepancies.