Let’s go with the premise: The agency fires the employee, and the AJ reverses that removal. If the agency then wants to PFR the AJ’s decision, it must put the employee back on the payroll as “interim relief” in order to have the Board accept the PFR. Some agencies put the employee back to work. Others keep them at home while they pay them. That is completely up to the agency.
However, there is no order for back pay or attorney fees during interim relief. That’s held in abeyance until a final decision on the PFR. Therefore, if the Board reverses the AJ and re-fires the employee (upholding the original removal), there’s nothing to pay back. The agency had the option of requiring the employee to report to work during interim relief in order to get paid. Therefore, if he was at work, he was earning his pay. No repayment necessary. If the agency does not put the employee back to work, and instead pays the employee to stay at home, then that’s on the agency, not the employee.