Here are the steps to reproduce this issue:
1. Configure the Agile Central integration as AC to PPM
2. Create a project in PPM and select the integration previously configured
3. Run the Synchronize Agile Central job to create the initiative in AC
4. Create more than 20 features for the initiative in AC
5. Assign a different owner to each feature previously created
6. Run the Synchronize Agile Central job again
Expected Result: All features are created as tasks, and owners are either created as team members or display in the Missing Resources portlet.
Actual Result: Some resources are missing.
CA PPM versions 15.3 and 15.4.
This issue is caused due to a defect, DE40517.
Defect DE40517 has been fixed in the upcoming release of CA PPM.