This article was sent to me by an immigration attorney who worked on our K1 visa then. Although, we filed the I-751 without his service but he's so kind enough to answer my immigration querries.

He said that he got this article from AILA website: http://www.aila.org/RecentPosting/RecentPostingList.aspx .

I-751 Receipting Update
USCIS Service Center Operations has informed AILA liaison that a processing problem at TSC resulted in delays in issuing I-751 receipts, which included biometrics notices coming prior to the I-751 receipts themselves, as well as biometrics notices and receipts bearing different file numbers. USCIS is working on the problem and expects resolution in the very near future. AILA Doc. No. 08041668.

I guess, there's some kind of a computer problem or whatever in TSC, thus resulting to delay of issuance of NOA's/Extension letters. They realllllly sucks!

The next question: Who long is the "very near future" would be?

Rose L

Thanks. That notice was issued, btw on April 16, 2008. The problem has been around since at least the first week of February. Nice of them to finally notice. Also, it only mentions delays of the receipts so that biometrics appointments arrive first, as if the receipts have actually arrived, albeit after the biometrics notices. The problem isn't the biometrics arriving first and the NOAs arriving second - it is that the NOAs are not arriving at all. They are not merely 'delayed'. I sure hope they know what the real problem is. The way this document is worded leaves room for doubt.

I wonder if this explains why received a duplicate receipt on 4/10. Hmmmm.....