How does it works "Expected Recall Date"

Hello All

I'm wondering if you can help me to clarify a concern on the Employee Master P0801EMP:

Once the customer change the Pay status for an Empployee to 1 (Paid Leave of Abbsence), they enter Leave Begin Date and also they wante to enter Expected Recall Date and leave the Termination Date in blank, however, when they try to save changes, the system trown an error, saying that the Termination date cannot be blank or cannot be less than Expected Recall Date.

Could you explain if the system works as designed and if so, the why??

I would like to have a technical explanation for my customer.