How to get both AAdhar and PAN details from candidate

We want to get both Aadhar and Pan details from candidate.

In Application flow we made National identifier block as mandatory but when candidate is selecting only one like Aadhar or Pan details system is allowing to submit application.

System is not blocking or showing validation error please enter both PAN and Aadhar details if one is missed.

How can we gather both Aadhar or Pan details from candidate so both details should flow to core hr

Please find attachment for more details and provide clarification.