FYI - an article on murthy.com
As regular readers of MurthyDotCom and the MurthyBulletin know, priority dates have retrogressed for EB3 professional / skilled workers from India, mainland China, and the Philippines. The dates have also retrogressed for all EB3 unskilled worker cases. Many people were able to file their I-485, Applications for Adjustment of Status (AOS), prior to retrogression's having taken effect, at a time when all priority dates were current and available. The same holds true for people who are processing their green cards through consular processing (CP) rather than AOS. Since a visa number must be available in order to approve an AOS or CP, these cases cannot be approved until the particular priority date assigned to the case once again becomes current. This leaves the question as to whether the U.S. Citizenship and Immigration Services (USCIS) or U.S. Department of State (DOS) will continue to take any processing action on these cases while the priority date is unavailable. The answer is yes.
If priority dates retrogress after the USCIS has received an AOS filing or the DOS has received a timely CP application, the USCIS or DOS may continue processing the case. For example, persons with pending I-485s, may be called for fingerprinting. This is not a cause for concern. It is also not necessarily connected in any way to the end of retrogression or the priority date becoming current at any point in the near future. It is just a routine part of the case that should be handled in a normal, routine manner.
Anyone with a pending AOS or CP application, who is contacted by the USCIS or DOS for further processing of any kind, whether fingerprinting, Request for Evidence, or any other matter, should respond to the request within the allowed timeframe to avoid a denial of the case. Assuming everything is in order, the case will then remain in pending status until it, hopefully, can be approved once the priority date becomes current.