If he's truly a "senior" CIA official, he probably actually was a reservist for much of his career, and continued to claim leave for reserve duties after he was discharged. And payroll eventually did pick up on this, which sparked an HR investigation of his credentials, which turned out to be inflated, and only then did they start to look at what this guy was doing with all the money he was taking home. Payroll is probably the only entity in this story that was actually doing their damn job.

I'm curious why he was discharged now.