Adjustment of Status - I-485

I have my EB2 Interview on July 17th to obtain my I485 approval, and green card issuance. The interview went extremely well with no issues according to the IO. However, the IO during the interview found out some mixed up in some documents from a prior EB1 application that I got denied few years ago as USCIS never closed its I-485 despite its I-140 denial. The IO mentioned that USCIS might have merged the two files together, and they need to sort them out, Kill the EB1 file and associated I485. He mentioned that he would fix the issue in the field office, and I would her from them in the next 3 weeks with probably my green card approval. Few hours after the interview my case status changed to Interview Completed, and Case must be reviewed. However, in the next day my case changed to Case transferred, and new Office has jurisdiction. That Got me very concerned as I realized they send it back to NBC office in MO. Could you please advice to as why it was sent back to NBC office, and How long I should wait to get my green card mailed given that the issue is within USCIS system, and nothing about my application? Appreciate any advice what I can do to follow up on this issue. Thanks Guys.