Hi all,
I'm posting this in the hopes it'll save anybody else from going through the same hassle I have... I filed for AOS (I-485) along with EAD and AP (I-765 and I-131) in mid-May 2020. I received my biometrics appointments at the end of July for August 5.
Strangely, I got two letters with the same appointment date/time - one was for I-485 only (Code 3 biometrics - picture, signature, all ten fingerprints) and another for I-485 and I-765 (Code 2 - picture, signature, and index fingerprint).
Despite showing both letters to the receptionist on arrival at the ASC, she said I only needed to do the appointment notice for Code 2 as it also referenced the I-485. This is incorrect. The mistake I made was in not showing both notices to the biometrics technician anyway, which I think would have saved time/problems.
I had called both Tier 1 and Tier 2, and they said they could see that biometrics were applied to all of my applications and so to just wait. However, having done a lot of reading, and asking about other people's cases, it seems as if Code 3 biometrics are mandatory for I-485 and my case would have stayed in limbo until someone working my case realized that the Code 3 biometrics weren't captured, or conceivably my case could have been denied for failure to appear.
Today, I drove out to the ASC and luckily got an extremely kind and understanding officer at the door who let me in despite my appointment being for ~3 weeks ago. The biometrics technician then processed the Code 3 notice (ten fingerprints, photo, signature) and I was on my way. I'll be interested to see if this now leads to a case update online, as before everything was still showing as Fingerprint Fee Received, and Case Received.
All of that to say, unfortunately you can't trust that people working in the ASCs all have the same level of knowledge or will take their job seriously. At worst I've lost a few weeks of time, but I'm hoping this post might help some others avoid the sort of limbo state that some of the February 2020 filers are experiencing by not insisting on showing all your notices to the biometrics technician.
Good luck to everyone else!