There could be several reasons why the mandatory field is not being enforced in your Pega application. Here are a few things you can check to troubleshoot the issue:
Check the field configuration: Ensure that the field is marked as mandatory in the field configuration. Also, check if any condition is set to make the field optional based on any condition. You can review the field configuration by opening the case type rule and navigating to the 'Data Model' tab.
Check the harness configuration: The harness configuration can also impact the behavior of mandatory fields. Ensure that the harness has been configured to display the mandatory fields. You can review the harness configuration by opening the harness rule.
Check the validation rule: If the field has any validation rule, make sure that the validation rule is running on the case submission. You can verify this by checking the validation rule definition.
Check the submit button configuration: Ensure that the submit button is associated with the correct action that runs the validation rule. If the validation rule fails, the action should not proceed to the next stage.
Check the case flow configuration: Make sure that the flow configuration is set up to enforce the mandatory fields. You can review the flow configuration by opening the case type rule and navigating to the 'Process' tab.
If none of these troubleshooting steps help, you can review the PegaRULES log file to see if there are any errors or warnings related to the case submission. If the issue persists, you can reach out to Pega Support for further assistance.
I hope this helps. Let me know if you have any further questions or concerns.