My K1 petition for Vietnamese Fiancee was approved with NOA2 on April 1 2024, sent to NVC which issued a case number on June 26. However, we got a letter on the mail saying that "case was returned to USCIS and recent update on USCIS showed " department of state sent case to USCIS for review? I would like to share and learn from people around the world who have been in the same situation, what are the reasons, and finally the case would be successful for how long? Thank and good luck.