Delay in Passport Issuance after Visa Approval

Hello! I had my F1 visa interview at the Kolkata consulate on June 6 and it was approved. I still haven't received any updates on when I'll get my passport back. Apparently, as mentioned in the disclaimer on the CEAC tracking page, the status should change from 'Approved' to 'Issued'. However, some people saw updates after just 1 day! But it's been 3-4 days and still nothing for some of us. Is it normal? Any idea what might have happened?