The issue with nested repeating groups not rendering all information entered if the nested group is not populated.
In workflow configuration, the key value of "AutoDeleteBlankRepeatingFormAreas" is set as "True"
Follow the below steps:
1. Open Workflow Administration Site.
2. Select configuration.
3. Search for key: AutoDeleteBlankRepeatingFormAreas
4. Set value to "False"
5. Wait for 5 minutes or restart IIS.