請教8老師及各位：H1B email notice of approval 到真正收到 approval notice （I-7

7/24 USCIS emailed the employer that the H-1B has been approved and the Approval Notice will follow in mail.
可是到現在8/3雇主還沒收到信（然後才能轉給我）。會不會是寄丟？平時這兩步之間 要多久？謝謝。