This may be happening because the constituent has been dropped from a membership and the cancelled membership is still active for another constituent. To stop this from membership from appearing in the export you will need to adjust the export definition to exclude dropped members from the output. Follow the steps below to do this:
  1. Open up the export definition of the process
    1. Acknowledgment Letter
      1. Click Marketing and Communications > Acknowledgements
      2. Click the drop down arrow next to the letter and click edit
      3. Click the edit link next to Acknowledgement merge fields
      4. Under Selected Fields Click on the member field and click the filter icon above selected fields
      5. Under filter, choose selected member
      6. Drag Is dropped from fields to include records where and set it equal to No
      7. Click OK until you're back to your definition fields. 
      8. Click save and close
    2. Appeal Mailing
      1. Click Marketing and Communications > Appeal Mailings
      2. Click on the appeal mailing
      3. Click on the letters tab
      4. Click the drop down arrow next to the letter and click edit
      5. Click the edit link next to Appeal Mailing merge fields
      6. Under Selected Fields Click on the member field and click the filter icon above selected fields
      7. Under filter, choose selected member
      8. Drag Is dropped from fields to include records where and set it equal to No
      9. Click OK until you're back to your definition fields. 
      10. Click save and close
    3. Export Definitions (Packages)
      1. Click Marketing and Communications > Export Definitions 
      2. Click the drop down arrow next to the definition > Click edit
      3. Under Selected Fields Click on the member field and click the filter icon above selected fields
      4. Under filter, choose selected member
      5. Drag Is dropped from fields to include records where and set it equal to No
      6. Click OK until you're back to your definition fields. 
      7. Click save and close
    4. Export Definitions ( Exports)
      1. Click Administration > Export Definitions 
      2. Click the drop down arrow next to the definition > Click edit
      3. Under Selected Fields Click on the member field and click the filter icon above selected fields
      4. Under filter, choose selected member
      5. Drag Is dropped from fields to include records where and set it equal to No
      6. Click OK until you're back to your definition fields. 
      7. Click save and close
  2. After the export definition is edited re-run your export process and download the output