The walk-ins fucked up the process.
That is why there are still people from the 12/13th waiting because some adjudicators are busy looking at the new Biometrics arriving while some are stuck with the old applications instead of everyone working on the old ones.
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Self filed AOS │Apps Received By USCIS - 3/18/19
│Biometrics Done - 4/11/19
Interview Scheduled - 4/24/19│Interview Date - 5/31/19│AOS Approval - 5/31/19
Permanent Resident Card Received - 6/8/19